This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Reverse NSString text
i am new on objectovec. i have a array having strings. how to reverse each string?
which method of NSArray and NSstring will help me out?
i want reversed string in the array.
thanks
Create a method that will return a reversed string.
-(NSString *)reverseString:(NSString *)string{
NSString *reverseString=[NSString new];
for (NSInteger i=string.length-1; i>-1; i--) {
reverseString=[reverseString stringByAppendingFormat:#"%c",[string characterAtIndex:i]];
}
return reverseString;
}
In your any of the method :
NSMutableArray *names=[NSMutableArray arrayWithObjects:#"anoop",#"johnson",#"wasim",nil];
for (NSInteger i=0; i<names.count; i++) {
names[i]=[self reverseString:names[i]];
}
NSLog(#"%#",names);
Hope this help
NSString *str=textEntered.text;//
NSMutableArray *temp=[[NSMutableArray alloc] init];
for(int i=0;i<[str length];i++)
{
[temp addObject:[NSString stringWithFormat:#"%c",[str characterAtIndex:i]]];
}
temp = [NSMutableArray arrayWithArray:[[temp reverseObjectEnumerator] allObjects]];
NSString *reverseString=#"";
for(int i=0;i<[temp count];i++)
{
reverseString=[NSString stringWithFormat:#"%#%#",reverseString,[temp objectAtIndex:i]];
}
NSLog(#"%#",reverseString);
NSString *str=textEntered.text;//
NSMutableArray *temp=[[NSMutableArray alloc] init];
for(int i=0;i<[str length];i++)
{
[temp addObject:[NSString stringWithFormat:#"%c",[str characterAtIndex:i]]];
}
temp = [NSMutableArray arrayWithArray:[[temp reverseObjectEnumerator] allObjects]];
NSString *reverseString=#"";
for(int i=0;i<[temp count];i++)
{
reverseString=[NSString stringWithFormat:#"%#%#",reverseString,[temp objectAtIndex:i]];
}
NSLog(#"%#",reverseString);
AnOther way for revers string NSStringEnumerationOptions
- (NSString *)reverseString:(NSString *)string {
NSMutableString *reversedString = [[NSMutableString alloc] init];
NSRange fullRange = [string rangeOfString:string];
NSStringEnumerationOptions enumerationOptions = (NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences);
[string enumerateSubstringsInRange:fullRange options:enumerationOptions usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
[reversedString appendString:substring];
}];
return reversedString;
}
Use
unichar c[yourstring.Length];
NSRange raneg={0,yourstring.Length};
[yourstring getCharacters:c range:raneg];
//c will be an array of your string do what ever you wish
Use this one to reverse your string and then store back to your array at same index.
-(NSString*)reverseString:(NSString*)string {
NSMutableString *reversedString;
int length = [string length];
reversedString = [NSMutableString stringWithCapacity:length];
while (length--) {
[reversedString appendFormat:#"%c", [string characterAtIndex:length]];
}
return reversedString;
}
But if you have mutable string then you can create a category
#interface NSMutableString (Reverse)
- (void)reverseString;
#end
#implementation NSMutableString (Reverse)
- (void)reverseString {
for (int i = 0; i < self.length/2; i++) {
int l = self.length - 1 - i;
NSRange iRange = NSMakeRange(i, 1);
NSRange lRange = NSMakeRange(l, 1);
NSString *iStr = [self substringWithRange:iRange];
NSString *lStr = [self substringWithRange:lRange];
[self replaceCharactersInRange:iRange withString:lStr];
[self replaceCharactersInRange:lRange withString:iStr];
}
}
#end
And then you can use this category method like this
NSArray *arr = [NSArray arrayWithObjects:[#"hello" mutableCopy], [#"Do it now" mutableCopy], [#"Test string, 123 123" mutableCopy], nil];
NSLog(#"%#",arr);
[arr makeObjectsPerformSelector:#selector(reverseString)];
NSLog(#"%#",arr);
Related
This question already has answers here:
How would I combine two arrays in Objective-C?
(2 answers)
Closed 9 years ago.
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSError *error;
json = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSLog(#"json.... %#",json);
id jsonObject = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingAllowFragments error:nil];
NSLog(#"jsonObject=%#", jsonObject);
NSDictionary *checkArray=[json valueForKey:#"ND"];
NSArray *tel = [checkArray valueForKey:#"FN"];
testArray = [[NSMutableArray alloc]init];
testArray1 = [[NSMutableArray alloc]init];
newsarray = [[NSMutableArray alloc]init];
for (id photo in tel)
{
if (photo == [NSNull null])
{
NSString *test8;
test8 = #"empty";
[testArray addObject:test8];
}
else
{
// photo isn't null. It's an array
NSArray *innerPhotos = photo;
[testArray addObject:photo];
}
}
NSArray *tel1 = [checkArray valueForKey:#"LN"];
for (id photo1 in tel1)
{
if (photo1 == [NSNull null])
{
NSString *test8;
test8 = #"empty";
[testArray1 addObject:test8];
}
else
{
// photo isn't null. It's an array
//NSArray *innerPhotos1 = photo1;
[testArray1 addObject:photo1];
}
}
newsarray = [NSMutableArray arrayWithArray:[testArray arrayByAddingObjectsFromArray:testArray1]];
NSLog(#"testArray =%#",newsarray);
here i want to combine two array values "testArray" and "testArray1"
my mutablearray values are
testArray = aa, bb, cc, dd...
testArray1= xx, yy, zz, ss...
i would like to expect my output like
aa xx, bb yy, cc zz, dd ss
Try this:
for (int i=0;i<[testArray count];i++){
NSString *tmpObject=[NSString stringWithFormat:#"%# %#",
[testArray objectAtIndex:i],
[testArray1 objectAtIndex:i]];
[newArray addObject tmpObject];
tmpObject=nil;
}
you can do something like below..
NSMutableArray *aryFinal=[[NSMutableArray alloc]init];
int count = [testArray count]+[testArray1 count];
for(int i=0;i<count;i++)
{
if(i%2==0)
[aryFinal addobject:[testArray objectAtIndex:i]];
else
[aryFinal addobject:[testArray1 objectAtIndex:i]];
}
let me know it is working or not!!!
NSMutableArray *array1 = [NSMutableArray arrayWithObjects:#"AA",#"BB",#"CC" nil];
NSArray *array2 = [NSArray arrayWithObjects:#"XX",#"YY",#"ZZ" nil];
for (int i=0; i<[array1 count];i++)
[array1 replaceObjectAtIndex:i
withObject:[NSString stringWithFormat:#"%# %#",
array1[i],
array2[i]]];
NSLog(#"%#",array1);
Output:
"AA XX","BB YY","CC ZZ"
To simply add two arrays:
[testArray setArray: testArray1];
But if you want desired result:
NSMutableArray *arrFinal=[[NSMutableArray alloc]init];
for(int i = 0; i < (testArray.count + testArray1.count); i++)
{
if(i%2 == 0)
[arrFinal addobject:[testArray objectAtIndex:i]];
else
[arrFinal addobject:[testArray1 objectAtIndex:i]];
}
Do not need to go for third array. You can use replaceObjectAtIndex method of NSMutableArray.
This way..
NSMutableArray *array1 = [NSMutableArray arrayWithObjects:#"aa",#"bb", nil];
NSArray *array2 = [NSArray arrayWithObjects:#"xx",#"yy", nil];
for (int i=0; i<[array1 count];i++)
[array1 replaceObjectAtIndex:i withObject:[NSString stringWithFormat:#"%# %#",array1[i],array2[i]]];
for aa xx, bb yy, cc zz, dd ss output:
int i=-1;
for(int k =0;k<[testArray1 count];++k)
{
i=i+2;
[testArray insertObject:[testArray1 objectAtIndex:k] atIndex:i];
}
NSMutableArray *array1,*array2;
//////array1 and array2 initialise it with your values
NSMutableArray *finalArray = [[NSMutableArray alloc]init]
int totalcount = 0;
if (array1.count > array2.count) {
totalcount = array1.count;
}
else
totalcount = array2.count;
for (int i = 0; i<totalcount; i++) {
if (i <= array1.count-1) {
[finalArray addObject:[array1 objectAtIndex:i]];
}
if (i <= array2.count-1) {
[finalArray addObject:[array2 objectAtIndex:i]];
}
}
NSMutableString *str =#"abcdefg123";
I want random the every character to a new String like this #"f1ad2g3be2".
NSMutableString *str1 = [[NSMutableString alloc]initWithString:str];
NSMutableString *str2 = [[NSMutableString alloc] init];
while ([str1 length] > 0) {
int i = arc4random() % [str1 length];
NSRange range = NSMakeRange(i,1);
NSString *sub = [str1 substringWithRange:range];
[str2 appendString:sub];
[str1 replaceOccurrencesOfString:sub withString:#"" options:nil range:range];
}
[str1 release];
str2 is what u want
Quite simple. First you must break up the characters into an array to work with. Then you swap the letters X many times, I choose to do this so every character will be swapped
NSString *str =#"abcdefg123";
int length = str.length;
NSMutableArray *letters = [[NSMutableArray alloc] init];
for (int i = 0; i< length; i++) {
NSString *letter = [NSString stringWithFormat:#"%c", [str characterAtIndex:i]];
[letters addObject:letter];
}
for (int i = 0; i<length; i++) {
int value = arc4random() % (length-1);
NSLog(#"Value is : %i", value);
[letters exchangeObjectAtIndex:i withObjectAtIndex:value];
}
NSString *results = [letters componentsJoinedByString:#""];
NSLog(#"The string before : %#", str);
NSLog(#"This is the string now : %#", results);
I have a string with certain pattern. I need to search for the pattern and replace the string inside that pattern. For eg :
NSString *string = #"{Hello} ({World}) ({How}) ({Are}) ({You})";
NSString *result = nil;
// Determine "{" location
NSRange startRange = [string rangeOfString:#"{" options:NSCaseInsensitiveSearch];
if (startRange.location != NSNotFound)
{
// Determine "}" location according to "{" location
NSRange endRange;
endRange.location = startRange.length + startRange.location;
endRange.length = [string length] - endRange.location;
endRange = [string rangeOfString:#"}" options:NSCaseInsensitiveSearch range:endRange];
if (endRange.location != NSNotFound)
{
// bracets found: retrieve string between them
startRange.location += startRange.length;
startRange.length = endRange.location - startRange.location;
result = [string substringWithRange:startRange];
}
}
Here I am able to extract the first substring that is between "{ }" ie - "Hello" but I also need to continue the check and want to extract other strings.
Try this one:
NSString *string = #"{Hello} ({World}) ({How}) ({Are}) ({You})";
//NSString *result = nil;
// Determine "{" location
NSArray *array=[string componentsSeparatedByString:#"{"];
for(NSString *str in array){
NSString *newString=[[str componentsSeparatedByString:#"}"] objectAtIndex:0];
NSLog(#"%#",newString);
}
try this :
NSString *string = #"{Hello} ({World}) ({How}) ({Are}) ({You})";
NSMutableString *result = [[NSMutableString alloc] init];
NSArray *tempArray = [[string componentsSeparatedByString:#" "] mutableCopy];
for (int i=0; i < [tempArray count]; i++)
{
NSString *tempStr = [tempArray objectAtIndex:i];
NSRange startRange = [tempStr rangeOfString:#"{" options:NSCaseInsensitiveSearch];
if (startRange.location != NSNotFound)
{
// Determine "}" location according to "{" location
NSRange endRange;
endRange.location = startRange.length + startRange.location;
endRange.length = [tempStr length] - endRange.location;
endRange = [tempStr rangeOfString:#"}" options:NSCaseInsensitiveSearch range:endRange];
if (endRange.location != NSNotFound)
{
// bracets found: retrieve string between them
startRange.location += startRange.length;
startRange.length = endRange.location - startRange.location;
//result = [tempStr substringWithRange:startRange];
[result appendString:[NSString stringWithFormat:#"%# ",[tempStr substringWithRange:startRange]]];
NSLog(#"%# ",result);
}
}
}
Take care for release for tempArray and result
I happen to have this code lying around. I think it does exactly what you want. I implemented it as a category on NSString. You use it like this:
NSString *template = #"{Hello} ({World}) ({How}) etc etc";
NSDictionary *vars = [NSDictionary dictionaryWithObjectsAndKeys:
#"Bonjour", #"Hello",
#"Planet Earth", #"World",
#"Como", #"How",
// etc.
nil];
NSString *expandedString = [template stringByExpandingTemplateWithVariables:vars];
// expandedString is #"Bonjour (Planet Earth) (Como) etc etc"
Here's the code.
File NSString+TemplateExpansion.h
#import <Foundation/Foundation.h>
#interface NSString (TemplateExpansion)
- (NSString *)stringByExpandingTemplateWithVariables:(NSDictionary *)dictionary;
#end
File NSString+TemplateExpansion.m
#import "NSString+TemplateExpansion.h"
#implementation NSString (TemplateExpansion)
- (NSString *)stringByExpandingTemplateWithVariables:(NSDictionary *)dictionary
{
NSUInteger myLength = self.length;
NSMutableString *result = [NSMutableString stringWithCapacity:myLength];
NSRange remainingRange = NSMakeRange(0, myLength);
while (remainingRange.length > 0) {
NSRange leftBraceRange = [self rangeOfString:#"{" options:0 range:remainingRange];
if (leftBraceRange.location == NSNotFound)
break;
NSRange afterLeftBraceRange = NSMakeRange(NSMaxRange(leftBraceRange), myLength - NSMaxRange(leftBraceRange));
NSRange rightBraceRange = [self rangeOfString:#"}" options:0 range:afterLeftBraceRange];
if (rightBraceRange.location == NSNotFound)
break;
NSRange beforeLeftBraceRange = NSMakeRange(remainingRange.location, leftBraceRange.location - remainingRange.location);
[result appendString:[self substringWithRange:beforeLeftBraceRange]];
remainingRange = NSMakeRange(NSMaxRange(rightBraceRange), myLength - NSMaxRange(rightBraceRange));
NSRange keyRange = NSMakeRange(NSMaxRange(leftBraceRange), rightBraceRange.location - NSMaxRange(leftBraceRange));
NSString *key = [self substringWithRange:keyRange];
NSString *value = [dictionary objectForKey:key];
if (value)
[result appendString:value];
}
[result appendString:[self substringWithRange:remainingRange]];
return result;
}
#end
In my app, I got Memory leaks in NSMutableArray, NSArray and NSString.
Here is the code.
NSString *subQuery = [NSString stringWithFormat:#"SELECT %# FROM tbl_lang WHERE glossary = '%#'",append1,glossaryName];
NSArray *subArray1 = [[[self returnExecuteQuery:subQuery] mutableCopy] autorelease];
[subArray addObjectsFromArray:subArray1];
NSString *columnQuery = [NSString stringWithFormat:#"select AutoID,%# from tbl_lang where glossary='%#'",lblshortName.text,glossaryName];
NSArray *newArray =[[[self returnExecuteQuery:columnQuery] mutableCopy] autorelease];
[langArray addObjectsFromArray:newArray];
NSMutableArray *tempArray = [[NSMutableArray alloc] init];
for (int i=0; i<[newArray count]; i++) {
NSString *cellText = [[newArray objectAtIndex:i] valueForKey:[NSString stringWithFormat:#"%#",lblshortName.text]];
if (cellText != (NSString *)[NSNull null] && ![cellText isEqualToString:#""] ) {
NSString *decodedString3 = [NSString stringWithUTF8String:[cellText cStringUsingEncoding:[NSString defaultCStringEncoding]]];
[tempArray addObject:[NSString stringWithFormat:#"%# : %#",lblshortName.text, decodedString3]];
}
else {
[tempArray addObject:#"<empty>"];
}
NSString *detail = #"_________________";
for (int j=0; j<[lableNameArray count]; j++) {
NSString *checkNull=[[subArray1 objectAtIndex:i] valueForKey:[NSString stringWithFormat:#"%#",[lableNameArray objectAtIndex:j]]];
if(checkNull != (NSString *)[NSNull null] && checkNull.length > 0)
{
NSString *decodedString4 = [NSString stringWithUTF8String:[checkNull cStringUsingEncoding:[NSString defaultCStringEncoding]]];
detail = [NSString stringWithFormat:#"%#\n%# : %# ",detail,[lableNameArray objectAtIndex:j],decodedString4];
}
}
[detailTextArray addObject:detail];
}
When I run in Instruments I got leaks in
-subArray1 in second line.
-detail (NSString) in second for loop.
And subArray and langArray are my global arrays.
If I remove mutableCopy from NSArray *newArray =[[[self returnExecuteQuery:columnQuery] mutableCopy] autorelease]; and NSArray *subArray1 = [[[self returnExecuteQuery:subQuery] mutableCopy] autorelease]; then subArray and langArray doesnot retain values.
How to avoid memory leak in this code?
Olease try this one, in above code you are creating two many objects that belong to autorelease pool here is one version where I tried to handle release of those string variables.
Second this is that the leak of detail is because you are de-referencing it many times in your code. And for subArray1 please see the comment
NSMutableString *subQuery =[ [NSMutableString alloc] initWithFormat:#"SELECT %# FROM tbl_lang WHERE glossary = '%#'",append1,glossaryName];
// please make returnExecuteQuery's returned array autorelease if it is not.
NSArray *subArray1 = [[self returnExecuteQuery:subQuery] mutableCopy] ;
[subArray addObjectsFromArray:subArray1];
[subQuery release];
NSMutableString *columnQuery ==[ [NSMutableString alloc] initWithFormat:#"select AutoID,%# from tbl_lang where glossary='%#'",lblshortName.text,glossaryName];
NSArray *newArray =[[self returnExecuteQuery:columnQuery] mutableCopy] ;
[langArray addObjectsFromArray:newArray];
[columnQuery relese];
NSMutableArray *tempArray = [[NSMutableArray alloc] init];
for (int i=0; i<[newArray count]; i++) {
NSMutableString *tempKey = [[NSMutableString alloc]initWithFormat:#"%#",lblshortName.text]];
NSString *cellText = [[newArray objectAtIndex:i] valueForKey:tempKey];
[tempKey release];
if (cellText != (NSString *)[NSNull null] && ![cellText isEqualToString:#""] ) {
NSString *decodedString3 = [NSString stringWithUTF8String:[cellText cStringUsingEncoding:[NSString defaultCStringEncoding]]];
NSMutableString *tempString = [[NSMutableString alloc] initWithFormat:#"%# : %#",lblshortName.text, decodedString3]];
[tempArray addObject:tempString];
[tempString release];
}
else {
[tempArray addObject:#"<empty>"];
}
NSMutableString *detail = nil;
for (int j=0; j<[lableNameArray count]; j++)
{
detail = [[ NSMutableString alloc]initWithString:#"_________________"];
NSMutableString *key = [[NSMutableString alloc]initWithFormat:#"%#",[lableNameArray objectAtIndex:j]];
NSString *checkNull=[[subArray1 objectAtIndex:i] valueForKey:key];
[key release];
if(checkNull != (NSString *)[NSNull null] && checkNull.length > 0)
{
NSString *decodedString4 = [NSString stringWithUTF8String:[checkNull cStringUsingEncoding:[NSString defaultCStringEncoding]]];
[detail setString:[NSString stringWithFormat:#"%#\n%# : %# ",detail,[lableNameArray objectAtIndex:j],decodedString4]];
}
[detailTextArray addObject:detail];
[detail release];
}
}
[subArray1 release];
[newArray release];
UPDATE : Please do read comments in the code and reply back so that things could be improved.
NSMutableString *subQuery =[ [NSMutableString alloc] initWithFormat:#"SELECT %# FROM tbl_lang WHERE glossary = '%#'",append1,glossaryName];
//*****NOTE THIS POINT ----> please make returnExecuteQuery's returned array autorelease if it is not.
NSArray *subArray1 = [[self returnExecuteQuery:subQuery] mutableCopy] ;
[subArray addObjectsFromArray:subArray1];
[subQuery release];
NSMutableString *columnQuery ==[ [NSMutableString alloc] initWithFormat:#"select AutoID,%# from tbl_lang where glossary='%#'",lblshortName.text,glossaryName];
//*****NOTE THIS POINT ----> please make returnExecuteQuery's returned array autorelease if it is not.
NSArray *newArray =[[self returnExecuteQuery:columnQuery] mutableCopy] ;
[langArray addObjectsFromArray:newArray];
[columnQuery relese];
NSMutableArray *tempArray = [[NSMutableArray alloc] init];
for (int i=0; i<[newArray count]; i++) {
NSMutableString *tempKey = [[NSMutableString alloc]initWithFormat:#"%#",lblshortName.text]];
NSString *cellText = [[newArray objectAtIndex:i] valueForKey:tempKey];
[tempKey release];
if (cellText != (NSString *)[NSNull null] && ![cellText isEqualToString:#""] ) {
NSString *decodedString3 = [NSString stringWithUTF8String:[cellText cStringUsingEncoding:[NSString defaultCStringEncoding]]];
NSMutableString *tempString = [[NSMutableString alloc] initWithFormat:#"%# : %#",lblshortName.text, decodedString3]];
[tempArray addObject:tempString];
[tempString release];
}
else {
[tempArray addObject:#"<empty>"];
}
NSMutableString *detail = [[ NSMutableString alloc]initWithString:#"_________________"];
for (int j=0; j<[lableNameArray count]; j++)
{
NSMutableString *key = [[NSMutableString alloc]initWithFormat:#"%#",[lableNameArray objectAtIndex:j]];
NSString *checkNull=[[subArray1 objectAtIndex:i] valueForKey:key]; //also here if you note you are using subArray1 not subArray?
[key release];
if(checkNull != (NSString *)[NSNull null] && checkNull.length > 0)
{
NSString *decodedString4 = [NSString stringWithUTF8String:[checkNull cStringUsingEncoding:[NSString defaultCStringEncoding]]];
[detail setString:[NSString stringWithFormat:#"%#\n%# : %# ",detail,[lableNameArray objectAtIndex:j],decodedString4]];
break;//I am not sure why you are checking this condition but assume that you want to get NOT NULL VALUE and add it to array?
}
}
[detailTextArray addObject:detail];
[detail release];
}
[subArray1 release];
[newArray release];
UPDATE 2:
if(checkNull != (NSString *)[NSNull null] && checkNull.length > 0)
{
NSString *decodedString4 = [NSString stringWithUTF8String:[checkNull cStringUsingEncoding:[NSString defaultCStringEncoding]]];
[detail appendFormat:#"%#\n%# : %# ",detail,[lableNameArray objectAtIndex:j],decodedString4]];
}
Thanks,
Not sure what is causing the memory leak, but this may help. This is a more direct way of copying the arrays, and may result in avoiding the leak:
NSArray *langArray =[[NSArray alloc] initWithArray: [self returnExecuteQuery:columnQuery] copyItems: YES];
This basically makes a one-level deep copy of the array returned by returnExecuteQuery. You can read about it in more detail in Collections Programming Topics.
I'm not sure how mutableCopy works and that may have something to do with the leak. If it copies the objects in the old array & then adds them to the new array, they may enter the array with a retain count of 2 (1 from the copy, and 1 from being added to an array.) It doesn't make much sense that it should work this way. But, if it does, that could account for the leak.
You could start by releasing your tempArray once done with it (after the loops).
Often, the higher levels leaks are hidden in the flood of lower level ones (ie a container leaking causes all its content to be leaked as well), which might be the case for your string.
Using mutableCopy] autorelease]; is fine by the way.
I am writing a program which prints the reverse of a string in a textfield, taking input text from the other textfield. When I press enter after entering text into one textfield the result(reverse) should be dispalyed in the other text field.
I have tried like this, but am getting weird results.
.h file:
#import <UIKit/UIKit.h>
#interface reverseVC : UIViewController {
UITextField *textEntered;
UITextField *textDisplay;
}
#property (nonatomic,retain) IBOutlet UITextField *textDisplay;
#property (nonatomic,retain) IBOutlet UITextField *textEntered;
- (NSMutableArray*) stringReverse;
- (IBAction) enter;
#end
.m file
- (NSMutableArray *) stringReverse
{
NSString *value = textEntered.text;
NSArray *tempArray = [[[NSArray alloc] initWithObjects:value,nil] autorelease];
NSMutableArray *arr = [[[NSMutableArray alloc] init] autorelease];
for (int i=[tempArray count]-1; i>=0; i--)
{
[arr addObject:[tempArray objectAtIndex:i]];
NSLog(#"the object is:%c",arr);
}
return arr;
}
-(IBAction)enter
{
textDisplay.text = [NSString stringWithFormat:#"%c",[self stringReverse]];
}
Earlier got warnings like SIG_ABT and EXE_BAD_ACCESS before placing nil and autorelease in array initialisations. Now the warnings are solved but results undesiredly.
Where am I going wrong?
You insert the NSString object in your array. Its count is 1. You have to go from the end of the string to the beginning and append the character to a new string. You ca do it like this:
-(NSString*)reverseString:(NSString*)string {
NSMutableString *reversedString;
int length = [string length];
reversedString = [NSMutableString stringWithCapacity:length];
while (length--) {
[reversedString appendFormat:#"%C", [string characterAtIndex:length]];
}
return reversedString;
}
Another way to reverse strings is to use the reverse string enumerator.
- (NSString *)reverseString:(NSString *)string {
NSMutableString *reversedString = [[NSMutableString alloc] init];
NSRange fullRange = [string rangeOfString:string];
NSStringEnumerationOptions enumerationOptions = (NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences);
[string enumerateSubstringsInRange:fullRange options:enumerationOptions usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
[reversedString appendString:substring];
}];
return reversedString;
}
use this
NSString *str=textEntered.text;//
NSMutableArray *temp=[[NSMutableArray alloc] init];
for(int i=0;i<[str length];i++)
{
[temp addObject:[NSString stringWithFormat:#"%c",[str characterAtIndex:i]]];
}
temp = [NSMutableArray arrayWithArray:[[temp reverseObjectEnumerator] allObjects]];
NSString *reverseString=#"";
for(int i=0;i<[temp count];i++)
{
reverseString=[NSString stringWithFormat:#"%#%#",reverseString,[temp objectAtIndex:i]];
}
NSLog(#"%#",reverseString);
I revers my strings with a few lines of code. Rather late, but just putting it out there :)
- (NSString*) reverseMyString:(NSString*)theString
{
NSString *final = #"";
for(int i = theString.length-1; i>=0; i--)
final = [NSString stringWithFormat:#"%#%c", final, [theString characterAtIndex:i]];
return final;
}
NSString *str = #"hello";
int length = [str length];
NSLog(#"%d",length);
NSMutableString *rev = [[NSMutableString alloc] initWithCapacity:[str length]];
while (length > 0) {
--length;
[rev appendString:[NSString stringWithFormat:#"%c", [str characterAtIndex:length]]];
}
NSLog(#"%#", rev);
Using characterAtIndex doesn't work well with non-ascii characters.
- (NSString *)reverseMyString:(NSString *)string {
NSString *output = [[NSString alloc] init];
for(int i = string.length-1; i>=0; i--) {
output = [output stringByAppendingString:[string substringWithRange:NSMakeRange(i, 1)]];
}
return output;
}