I am writing a program for insertion sort.I am creating a class to read print and sort a vector of integers.I have created a vector of class and I want to call functions read,sort and print from vector of class created.How to do that ?
Thanks,
#include <iostream>
#include <vector>
using namespace std;
class sorting
{
private:
vector<int>arr;
public:
void read();
void sortt();
void print();
};
void sorting :: read()
{
int n;
cin>>n;
for(int i=0; i<n; i++)
{
int t;
cin>>t;
arr.push_back(t);
}
}
void sorting :: sortt()
{
int j,temp;
for(unsigned int i=0; i<arr.size(); i++)
{
temp=arr[i];
j=i;
while(temp<arr[j-1] && j>0)
{
arr[j]=arr[j-1];
j=j-1;
}
arr[j]=temp;
}
}
void sorting :: print()
{
for(unsigned int k=0; k<arr.size(); k++)
{
cout<<arr[k]<<"\t";
}
cout<<endl;
arr.clear();
}
int main()
{
vector<sorting>s;
s.read(); // giving an error
s.sortt(); // giving an error
return 0;
}
It should be sorting s; and not vector<sorting>. You defined those methods read() amd sortt() defined in the class sorting.
Thanks,
I got this answer searching in google accidentally in different websites,
It is like vectors(100)
So I can call
s[i].sortt()
s[i].print()
for objects of vector
Related
[1][I write a simple program in dart to print multiplication table but the output was not I Except][1]
void main{
int num=10;
for(var i=1;i<=10;++i){
print('$num*$i=$num');
}
}
this was my code
Finally I found the answer
var num = 10;
for (var i = 1; i < 10; i++) {
print("$num * $i = ${num * i}");
}
any other ways to print multiplication table in dart using for loop
You forget to add the parenthesis in the main function which acted like a function declaration.
And you also missed to multiply the result of the multiplication by i.
The correct code is :
void main(){
int num=10;
for(var i=1;i<=10;++i){
print('$num*$i=${num*i}');
}
}
instead of this:
void main{
int num=10;
for(var i=1;i<=10;++i){
print('$num*$i=$num');
}
}
void main()
{
int num =20;
for(int i=1;i<=10;i++)
{
print("num* $i = ${num*2}");
}
}
I have this block of code below, and I cant find out what that class ContractB : public: ContractA means?
#include
using namespace std;
class ContractA
{
unsigned int ether = 0;
public:
ContractA(unsigned int e) :ether(e) {}
auto sendEther() { return ether; }
};
class ContractB : public ContractA
{
unsigned int wei = 1;
public:
ContractB(unsigned int w) :wei(w) {}
auto sendWei() { return wei; }
};
int main()
{
ContractB b(0);
cout << b.sendEther() << " " << b.sendWei();
return 0;
}
It represents inheritance. 'public' is the access specifier that limits the most accessible level for the members inherited from the base class (ContractA).
You can read more about it here.
I have an assignment as following: Write a program will ask the user how many random numbers to generate. Then it will present a menu which has the options of Display, Average, Median, and Standard Deviation, Regenerate, and Quit. Without the use of a switch statement, or an if statements, or pointers to functions, have the program execute the user's selection from the menu. (Note: Function pointers are not allowed!)
This is what I have so far:
#include <iostream>
#include <cstdlib>
#include <array>
#include <cmath>
#include <stdlib.h>
#include <map>
using namespace std;
template <typename T> class wrapperclass
{
public:
static T myclass;
};
class Display
{
public:
static void myFunction(int random[], int num)
{
for(int i=0; i<num; ++i)
{
cout << random[i] <<endl;
}
}
};
class Average
{
public:
static double myFunction(int random[], int num)
{
double avg = 0;
for(int i=0; i<num; ++i)
{
avg += random[i];
}
return avg/num;
}
};
class Median
{
public:
static double myFunction(int random[], int num)
{
double mid = 0;
if(num % 2 == 0)
{
mid = (random[num/2] + random[num/2-1])/2;
}
else
{
mid = random[num/2];
}
return mid;
}
};
class StdDi
{
public:
static double myFunction(int random[], int num)
{
double avg=0;
double total=0;
for(int i=0; i<num; ++i)
{
avg += random[i];
}
avg = avg/num;
for(int i=0; i<num; ++i)
{
total += (avg-random[i])*(avg-random[i]);
}
total = total/num;
return sqrt(total);
}
};
class renerate
{
public:
static void myFunction(int)
{
}
};
class quit
{
public:
static void myFunction()
{
exit(EXIT_FAILURE);
}
};
int main()
{
int num = 0;
int option = 0;
map<int, class T> magic;
cout << "How many random numbers would u like to generate? " << endl;
cin >> num;
int random[num];
for(int i=0; i<num; ++i)
{
random[i] = rand() % 100 + 1;
}
cout << " Menu"<<endl
<< "1. Display"<<endl
<< "2. Average"<<endl
<< "3. Median"<<endl
<< "4. Standard Deviation"<<endl
<< "5. Renerate"<<endl
<< "6. Quit"<<endl;
cin >> option;
cout<<wrapperclass<Average>::myclass.myFunction(random, num);
return 0;
}
I'm about to directly pass the user input "option" into that "wrapperclass" like this "wrapperclass" so I can simply call the .myFunction since all classes have the same function name. but this won't work for c++ so is there any work around?
I actually have a small question. I want to create an attribute "function" which should be from the class function1, function2 or function3. Is there a way I can do that?
Here is the code:
double Uppersum::evalIntegral(double p_) {
if (functiontype == FUNKTION1){
Function1 function;
}
else if (functiontype == FUNKTION2) {
Function2 function;
}
else if (functiontype == FUNKTION3){
Function3 function;
}
function.setParameterP(p_);
double increment_h = (boundary_b - boundary_a)/num_subintervalls_m;
double sum = 0;
for (int index_i = 0; index_i < num_subintervalls_m -1; index_i++){
double x_1 = index_i * increment_h;
double x_2 = (index_i+1) * increment_h;
double y_1, y_2;
y_1 = function.evalFunctionValue(x_1);
y_2 = function.evalFunctionValue(x_2);
sum += increment_h * std::max(y_1, y_2);
}
}
class Function {
protected:
double parameter_p;
public:
void setParameterP(double p_);
virtual double evalFunctionValue(double x_)=0;
};
class Function1 : public Function {
public:
double evalFunctionValue(double x_);
};
Why not use inheritance, superclass has the virtual functions setParameterP and evalFunctionValue. and in subclasses, override those virtual functions.
here is the test code：
test.cpp
#include <iostream>
typedef enum{
FUNCTION1,
FUNCTION2,
FUNCTION3
}FunctionType;
using namespace std;
class super
{
public:
super(){}
~super(){}
virtual void setParameterP() = 0;
virtual void evalFunctionValue() = 0;
};
class func1:public super
{
public:
func1(){}
virtual void setParameterP(){cout<<"call setParameterP In func1"<<endl;}
virtual void evalFunctionValue(){cout<<"call evalFunctionValue In func1"<<endl;}
};
class func2:public super
{
public:
func2(){}
virtual void setParameterP(){cout<<"call setParameterP In func2"<<endl;}
virtual void evalFunctionValue(){cout<<"call evalFunctionValue In func2"<<endl;}
};
class func3:public super
{
public:
func3(){}
virtual void setParameterP(){cout<<"call setParameterP In func3"<<endl;}
virtual void evalFunctionValue(){cout<<"call evalFunctionValue In func3"<<endl;}
};
class FuncFactory
{
public:
static super* create(FunctionType var)
{
super* ret = nullptr;
switch (var)
{
case FUNCTION1:
ret = new func1();
break;
case FUNCTION2:
ret = new func2();
break;
case FUNCTION3:
ret = new func3();
break;
default:
cout <<"invalid FunctionType" << endl;
}
return ret;
}
};
int main(int argc, char** argv)
{
super* pFunc = FuncFactory::create(FUNCTION1);
pFunc->setParameterP();
pFunc->evalFunctionValue();
delete pFunc;
pFunc = FuncFactory::create(FUNCTION2);
pFunc->setParameterP();
pFunc->evalFunctionValue();
delete pFunc;
pFunc = FuncFactory::create(FUNCTION3);
pFunc->setParameterP();
pFunc->evalFunctionValue();
delete pFunc;
return 0;
}
here is the process result:
result
I have a class "PclProc" and I want to use std::sort.
I write a compare function in the same class because this comparing need the "in_ptr" which is a variable in the same class.
But as I did as following, there is always an error:
error: no matching function for call to
‘sort(std::vector::iterator, std::vector::iterator,
)’
std::sort(cloud_indice.indices.begin(),cloud_indice.indices.end(),PclProc::MyCompare);
bool PclProc::MyCompare(int id1, int id2)
{
return in_ptr->points[id1].z<in_ptr->points[id2].z;
}
float PclProc::MedianZDist(pcl::PointIndices cloud_indice)
{
std::sort(cloud_indice.indices.begin(),cloud_indice.indices.end(),PclProc::MyCompare);
int size=cloud_indice.indices.size();
float median_x,median_y;
...
Example of a functor being used for std::sort. vector D is the data, vector I is the indices to D. I is sorted according to D with std::sort using the functor. std::sort only creates one instance of class lessthan, then uses that one instance for all of the compares.
#include <algorithm>
#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <vector>
typedef unsigned int uint32_t;
#define SIZE 16
class example{
public:
std::vector<uint32_t> D; // data
std::vector<uint32_t> I; // indices
example(void)
{
D.resize(SIZE);
I.resize(SIZE);
for(uint32_t i = 0; i < SIZE; i++){
D[i] = rand()%100;
I[i] = i;
}
}
void displaydata(void)
{
for(size_t i = 0; i < SIZE; i++)
std::cout << std::setw(3) << D[I[i]];
std::cout << std::endl;
}
class lessthan // lessthan functor for std::sort
{
public:
const example &x;
lessthan(const example &e ) : x(e) { }
bool operator()(const uint32_t & i0, const uint32_t & i1)
{
return x.D[i0] < x.D[i1];
}
};
void sortindices(void)
{
std::sort(I.begin(), I.end(), lessthan(*this));
}
};
int main()
{
example x;
x.displaydata();
x.sortindices();
x.displaydata();
return 0;
}