Write a assign_obj.h file so that the assign_driver file will output the
following. When implementing assign_obj.h think about how efficient your program will run. You must
implement your assign_obj class using a dynamic array.
assign_obj:: assign_obj() function will just set size to zero
assign_obj:: assign_obj(std::string s) function will go through each character of string and convert it to uppercase and push it the last of A
std::ostream& operator<<(std::ostream & out, assign_obj & obj) function will go through each data in obj.A vector and convert integer into string and
than output the data in this format [value:count value:count ....]
class assign_obj{
private:
struct item{
char value;
int count;
};
item *A;
int size;
public:
assign_obj();
assign_obj(std::string);
friend std::ostream& operator<<(std::ostream & out, assign_obj & obj);
}
int main(){
assign_obj ao1("dsdfdf");
std::cout << ao1 << std::endl;
}
This is the output that I want
[ D:1 S:1 D:1 F:1 D:1 F:1 ]
assign_obj:: assign_obj(){
size = 0;
}
assign_obj:: assign_obj(std::string s){
size = s.size();
for(int i = 0; i < s.size(); i++){
char c = std::toupper(s[i]);
A = new item{c,1};
}
}
# std::ostream& operator<<(std::ostream & out, assign_obj & obj){
std::cout<< "size: " << obj.size <<std::endl;
out << "[ ";
for(int i = 0; i < obj.size; i++){
out << obj.A[i].value << ":" << std::to_string(obj.A[i].count) << " ";
}
out << "]" << "\n";
return out;
}
This is my first time asking a question, so apologies if it is not done 100%:
I have a class which saves and loads a binary file with a specific data structure.
If the program creates an instance of the class, save the binary file, and creates another instance of the class to load/read the binary file consequently, everything seems 100% correct.
However, if I run the program to save the binary file and then run it again to load/read that binary file, it gives me a segmentation fault at the end.
The program still does everything it needs to do before the segmentation fault, except deconstructing the class at the end (obviously).
It looks like my allocation of the memory is not correct, but I am not sure where I am going wrong.
A simplified version of the code follow (also here: https://github.com/LenteDreyer/Tests.git )
Can someone see where I am going wrong?
class header file that save/loads the file
#ifndef __TESTS_MAP_HH__
#define __TESTS_MAP_HH__
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
typedef struct test_struct{
bool test_bool;
double test_double;
std::vector<double> test_vector;
} test_struct_t;
class map
{
private:
std::string m_path, m_str;
double m_double;
test_struct m_struct;
public:
map(const std::string& a_id);
void set_str(std::string a_str);
void set_double(double a_double);
void set_struct(test_struct a_struct);
void load_file();
void save_file() const;
void show_file() const;
~map();
};
#endif //__TESTS_MAP_HH__
class source file that save/loads the binary file
#include "map.hh"
map::map(const std::string& a_id)
{
m_path = a_id + ".bin";
m_str = "none";
m_double = 0.0;
m_struct = {false, 0.0};
}
void map::set_str(std::string a_str){
m_str = a_str;
}
void map::set_double(double a_double){
m_double = a_double;
}
void map::set_struct(test_struct a_struct){
m_struct = a_struct;
}
void map::load_file(){
std::ifstream l_inF;
l_inF.open(m_path.c_str(), std::ios::binary | std::ios::in);
l_inF.read((char*)&m_double,sizeof(double));
l_inF.read((char*)&m_struct,sizeof(test_struct_t));
size_t str_size;
l_inF.read((char*)&str_size, sizeof(str_size));
m_str.resize(str_size);
l_inF.read((char*)&m_str[0], str_size);
l_inF.close();
}
void map::save_file() const{
std::ofstream l_outF;
l_outF.open(m_path.c_str(), std::ios::binary | std::ios::out);
l_outF.write((char*)&m_double,sizeof(double));
l_outF.write((char*)&m_struct,sizeof(test_struct_t));
size_t str_size = m_str.size();
l_outF.write((char*)&str_size, sizeof(str_size));
l_outF.write((char*)&m_str[0], str_size);
l_outF.close();
}
void map::show_file() const{
std::cout << ">>-----------------------------------------------" << std::endl;
std::cout << ">> double : " << m_double << std::endl;
std::cout << ">> double : " << m_double << std::endl;
std::cout << ">> struct.bool : " << m_struct.test_bool << std::endl;
std::cout << ">> struct.double : " << m_struct.test_double << std::endl;
std::cout << ">> struct.vector : " << "size = " << m_struct.test_vector.size() << std::endl;
std::cout << ">> string : " << m_str << std::endl;
std::cout << ">>-----------------------------------------------" << std::endl;
}
map::~map(){}
main function case 1 works, and case 2 gives the segmentation fault.
#include "map.hh"
int main(int argc, char const *argv[])
{
std::string id = "mapfile";
int action = 0;
if(argc > 1) action = std::stoi(argv[1]);
else {
std::string input;
std::cout << "Enter case (1 or 2): ";
std::cin >> input;
action = std::stoi(input);
}
switch (action)
{
case 1:
{
// This works 100% (no errors and it saves/reads class perfectly)
std::vector<double> l_vect = {0.1, 0.0, 0.6};
test_struct save_struct = {true, 5.0, l_vect};
map test_save(id);
test_save.show_file();
test_save.set_double(8.0);
test_save.set_str("save this string");
test_save.set_struct(save_struct);
test_save.show_file();
test_save.save_file();
map test_load(id);
test_load.load_file();
test_load.show_file();
}
break;
case 2:
{
// gives segmentation error at the end of the program
map test_load(id);
test_load.load_file();
test_load.show_file();
}
break;
default:
break;
}
return 0;
}
Can someone tell my why my program prints wrong values?
I've mostly followed an youtube video how to use vectors. And the program which was written, i was able to run it. I tried to implement the same method for my program which is for cars (video was for students). But i'm having problems. Funny part is, that the student program ran well, i don't remember changing anything to it, and now it also doesn't print anything at all.
So i'm trying to make a program that inputs car brand, year and price into a vector of a class and then print out all the stored information. But i'm currently getting mixed results.
I'm either getting blank spaces for results or some huge numbers and blank space for the brand (string)
When i'm not using references & i get blank results, with & i get what i've written below.
Does anyone have an idea?
When i input:
brand - Lambo
year - 1997
price 25000
I get:
Car brand:
Car year: 2686588
Car price: 6.95144e-308
main.cpp
#include <iostream>
#include <string>
#include "Car.h"
#include <vector>
using namespace std;
Car::Car(){
}
Car::Car(string brand, int year, double price){
brand;
year;
price;
}
Car::~Car(){
}
string Car::getBrand() const{
return brand;
}
int Car::getYear() const{
return year;
}
double Car::getPrice()const{
return price;
}
void Car::setBrand(string brand){
brand;
}
void Car::setYear(int year){
year;
}
void Car::setPrice(double price){
price;
}
void enterData(vector<Car>&);
void showData(const vector<Car>&);
int main(){
vector<Car> myGarage;
int chc;
cout << "-- M A I N M E N U --\n\n";
do{
cout << "Please make a choice\n\n";
cout << "1. Enter car details" << endl;
cout << "2. Show car details" << endl;
cout << "3. Exit" << endl;
cin >> chc;
switch(chc){
case 1:
enterData(myGarage);
break;
case 2:
showData(myGarage);
break;
case 3:
cout << "Have a nice day!";
break;
}
}
while(chc != 3);
}
void enterData(vector<Car>& newMyGarage){
string brand;
int year;
double price;
cout << "How many cars are in your garage?";
int garageSize;
cin >> garageSize;
for(int i = 0; i < garageSize; i++){
cout << "Car brand: ";
cin >> brand;
cout << "Car year: ";
cin >> year;
cout << "Car price: ";
cin >> price;
Car newCar(brand, year, price);
newMyGarage.push_back(newCar);
cout << endl;
}
}
void showData(const vector<Car>& newMyGarage){
unsigned int size = newMyGarage.size();
for(unsigned int s = 0; s < size; s++){
cout << "Car brand: " << newMyGarage[s].getBrand() << endl;
cout << "Car year: " << newMyGarage[s].getYear() << endl;
cout << "Car price: " << newMyGarage[s].getPrice() << endl;
cout << endl;
}
}
header file Car.h
#ifndef CAR_H_INCLUDED
#define CAR_H_INCLUDED
#include <iostream>
#include <string>
using namespace std;
class Car{
public:
string brand;
int year;
double price;
Car();
Car(string, int, double);
~Car();
string getBrand() const;
int getYear() const;
double getPrice() const;
void setBrand(string);
void setYear(int);
void setPrice(double);
};
#endif // CAR_H_INCLUDED
I am doing a project for a class writing C-String-editing functions. 3/5 of the functions I have to write change the size of the char arrays I have to use, and they are being read through an ifstream input. Here is the program:
#include <iostream>
#include <fstream>
using namespace std;
void stringCopy(char *A, char *B);
bool stringCompare(char *A, char *B);
void stringConcatenation(char *A, char *B); //added const to make sure b is never changed
int stringPosition(char *A, char B);
int stringLength(char *A);
//-------------------MY-FUNCTIONS----------------------
int cStringLen(const char*); //finds string length, but doesn't account for null char
void reSize(char*&, int len, int newLen);
void input(char*& A, istream& is);
void printMessage(const char* word1, const char* word2, const char* message);
int main()
{
ifstream ifs{"input.txt"};
ofstream ofs{"output.txt"};
char* word1 = "";
char* word2 = "";
input(word1, ifs);
input(word2, ifs);
printMessage(word1, word2, "stringCopy()");
stringCopy(word1, word2);
printMessage(word1, word2, "after stringCopy()");
cout << endl;
input(word1, ifs);
input(word2, ifs);
printMessage(word1, word2, "stringCompare()");
if(stringCompare(word1, word2))
{
cout << "They match!" << endl;
}
else
{
cout << "They don't match!" << endl;
}
stringCopy(word1, word2);
printMessage(word1, word2, "comparing after stringCopy()");
if(stringCompare(word1, word2))
{
cout << "They match!" << endl;
}
else
{
cout << "They don't match!" << endl;
}
cout << endl;
input(word1, ifs);
input(word2, ifs);
printMessage(word1, word2, "stringConcatenation()");
stringConcatenation(word1, word2);
printMessage(word1, word2, "after stringConcatenation()");
cout << endl;
input(word1, ifs);
input(word2, ifs);
printMessage(word1, word2, "stringPosition()");
cout << "Searching for 'm' in word1..." << endl << "position returned is: " << stringPosition(word1, 'm') << endl;
cout << "Searching for 'n' in word2..." << endl << "position returned is: " << stringPosition(word2, 'n') << endl;
cout << endl;
input(word1, ifs);
cout << "stringLength()" << endl;
cout << "word1: " << word1 << endl;
cout << "The length of word1 is: " << stringLength(word1) << endl;
cout << "after stringLength()" << endl;
cout << "word1: " << word1 << endl;
return 0;
}
void stringCopy(char *A, char *B)
{
///GETTING THE SIZES OF BOTH ARRAYS
int counterA = cStringLen(A) + 1;
int counterB = cStringLen(B) + 1;
///MAKES SURE BOTH ARE THE SAME SIZE BEFORE COPYING
if(counterA < counterB)
{
reSize(A, counterA, counterB);
}
else
{
reSize(A, counterB, counterA);
}
///THE COPY
for(int i = 0; i < counterB; i++) *(A + i) = *(B + i); //each character is copied to A from B
}
bool stringCompare(char *A, char *B)
{
///getting length of one string
int counter = cStringLen(A);
///will move through string until diff char found
for(int i = 0; i < counter + 1; i++)
{
if(*(A + i) != *(B + i))
{
return false;
}
}
return true;
}
void stringConcatenation(char *A, char *B) //added const to make sure b is never changed
{
///getting length of both strings
int counterA = cStringLen(A)+1;
int counterB = cStringLen(B)+1;
///putting the length of both together for new string
const int COUNTERS = counterA + counterB - 1;
///making A the size of both strings - 1
reSize(A, counterA, COUNTERS);
///copying b to the parts of a past the original
for(int i = 0; i < counterB; i++)
{
*(A + (counterA - 1) + i) = *(B + i); //will override the '/0' char of A
}
}
int stringPosition(char *A, char B)
{
int counter = cStringLen(A) + 1;
///searching through string for char
for(int i = 0; i < counter; i++)
{
if(*(A + i) == B)
{
return i; //found!
}
}
///checking if b == '\0' and a '\0' isn't found somewhere before last spot of A
if(B == '\0')
{
return counter;
}
return -1; //not found
}
int stringLength(char *A)
{
int counter = cStringLen(A) + 1;
char* car = new char[counter + 1];
for(int i = 0; i < counter; i++)
{
*(car + 1 + i) = *(A + i);
}
*(car + 0) = counter;
delete[] A;
A = car;
/**
* Will take string as param.
* Shifts all characters to the right by one and store the length of the string in position 0.
- Length doesn't include position 0.
*/
return counter; //temp
}
//-----------------------------------------MY FUNCTIONS---------------------------------------------------------------------------
int cStringLen(const char* A) //finds string length, but doesn't account for null char
{
int counter = 0;
while(*(A + counter) != '\0')
{
counter++;
}
return counter;
}
void reSize(char*& A, int len, int newLen)
{
char* car = new char[newLen];
for(int i = 0; i < newLen; i++)
{
if(i < len)
{
*(car + i) = *(A + i);
}
else if(i >= len && i < newLen)
{
*(car + i) = '\0';
}
}
delete[] A;
A = car;
}
void input(char*& A, istream& is)
{
int wordSize = 0;
int arrSize = 1;
char c = 'o'; //checking char
char* car = new char[arrSize];
while((!(is.eof())) && (c != ' ' && c != '\t' && c != '\n'))
{
is.unsetf(ios_base::skipws);
is >> c;
if(is.eof())
{
delete[] A;
A = car;
return;
}
if(c != ' ' && c != '\t' && c != '\n')
{
if(wordSize == arrSize)
{
reSize(car, arrSize, arrSize * 2);
}
*(car + wordSize) = c;
}
wordSize++;
}
is.setf(ios_base::skipws);
delete[] A;
A = car;
}
void printMessage(const char* word1, const char* word2, const char* message)
{
cout << message << endl;
cout << "word1: " << word1 << endl << "word2: " << word2 << endl;
}
I thought I got it all done just fine. Keep in mind that I added the "&" operator after each of the pointer parameters already. Here is how they were before:
void stringCopy(char *&A, char *B);
bool stringCompare(char *A, char *B);
void stringConcatenation(char *&A, char *B); //added const to make sure b
is never changed
int stringPosition(char *A, char B);
int stringLength(char *&A);
But, when I got to class, my teacher said we weren't allowed to change the function headers in any way. So, I am stuck passing by value for the assignment. The problem is that I have no way of changing the c-strings outside the editing functions now. Any changes I do to them stay inside there.
It all compiles just fine, and, if I make the pointers pass-by-reference, the program runs flawlessly. I am just wondering how I could change the values of the c-strings outside of the editing functions. This assignment is starting to become a pain (so many f***ing restrictions).
I think what your teacher wants you to do is to change the value at the character pointer instead of creating a new string.
So instead trying to reassigning parameter A to a new char* you change the value that A points to in memory. That way the method that called your function still points to that same memory and when they access that location the get the value you changed from within your function.
I've been working on a program that will do a couple of equations in regards to audio, SPL, etc.
I decided to have the main class file present the user with an option to choose what equation he wants to do, while the equations are housed in another class file.
Atm, the main class file is setup just to test maxPeakSPL(), yet I can't get it to run.
main.cpp
//Kh[a]os
#include "equations.h"
#include <iostream>
void mainLoop();
int maxSPL = 0;
int main()
{
std::cout << "Created by Kh[a]os" << std::endl << std::endl;
mainLoop();
return 0;
}
void mainLoop()
{
std::cout << "hi";
maxSPL = equations::maxPeakSPL();
std::cout << std::endl << maxSPL << "db" << std::endl << std::endl;
}
equations.h
#ifndef EQUATIONS_H
#define EQUATIONS_H
#include <string>
class equations
{
public:
equations();
static int maxPeakSPL();
protected:
private:
};
#endif // EQUATIONS_H
equations.cpp
#include "equations.h"
#include <iostream>
#include <string>
equations::equations()
{
}
static int maxPeakSPL()
{
int Sens = 0;
double Distance = 0;
int Watts = 0;
int sWatts = 2;
int eWatts = 0;
double maxSPL = 0;
double counter = 0;
double wall = 0;
std::string corner = "";
bool v = true;
std::cout << "Sensitivity (db): " << std::endl;
std::cin >> Sens;
std::cout << "Amplification (watts): " << std::endl;
std::cin >> Watts;
std::cout << "Listening Distance (meters): " << std::endl;
std::cin >> Distance;
std::cout << "Distance from Wall (ft): " << std::endl;
std::cin >> wall;
std::cout << "Are you they in a corner? (y/n): " << std::endl;
std::cin >> corner;
maxSPL = Sens - (Distance*3 - 3);
while(v == true)
{
if (sWatts > Watts)
{
v = false;
eWatts = sWatts;
sWatts = sWatts/2;
Watts = Watts-sWatts;
counter = (double)Watts/(double)eWatts;
counter = counter*3;
maxSPL = maxSPL + counter;
}
if (v == true)
{
maxSPL = maxSPL + 3;
sWatts = sWatts*2;
}
}
if (wall <= 4)
maxSPL = maxSPL + 3;
if (corner == "Y" || corner == "YES" || corner == "y" || corner == "yes")
maxSPL = maxSPL + 3;
return maxSPL;
}
The error I get when I run it is: undefined reference to `equations::maxPeakSPL()'
I haven't a clue how to fix this, any assistance would be great. Thank you.
In your main, try putting the function before the main block. Include an underscore before the name of your directives/flags.