#include<iostream>
using namespace std;
class money
{
int rs;
int p;
public:
void setdata (int x , int y)
{rs=x; p=y;}
void show()
{ cout <<rs <<"." <<p; }
money operator += (int a) {
money temp;
temp.rs=rs+a.rs;
temp.p=p+a.p;
return (temp);
}
};
int main() {
money c1,c2;
c1.setdata(8,2);
c2=c1.operator+=(4);
c2.show();
}
Can someone tell me why the operator += overloading doesn't work?
My desiring output is 12.2 but the output i got is 16.2 .
I am sending 4 as argument and i want this argument is added in r (ruppee)
part
#include<iostream>
using namespace std;
class money
{
int rs;
int p;
public:
void setdata (int x , int y)
{rs=x; p=y;}
void show()
{ cout <<rs <<"." <<p; }
money& operator+=(int a)
{ rs += a; return *this; }
};
int main() {
money c1,c2;
c1.setdata(4,2);
c2=c1+=(4); //c2=c1.operator+=(4);
c2.show();
}
Try to use constructor correctly.
For example:
#include <iostream>
using namespace std;
class Example
{
public:
int x;
Example(int a)
{
x=a;
}
Example operator+(Example obj)
{
Example ans(0);
ans=x+obj.x;
return ans;
}
};
int main()
{
Example a(10),b(20);
Example ans=a+b;
cout<<ans.x<<endl;
return 0;
}
Related
#include <bits/stdc++.h>
using namespace std;
struct stu {
int n;
stu(int _n = 0):n(_n) { }
int add(int a, int b = n-1) {
return a + b;
}
};
int main() {
stu obj = stu(5);
cout << obj.add(10) << endl;
}
The compiler shows the message " invalid use of
non-static data member 'stu::n' ".
What is wrong with this code. Any help would be great.
Thanks.
You can't use default arguments this way. Consider writing two separate functions:
struct stu {
int n;
int add(int a, int b) { return a + b; }
int add(int a) { return a + n - 1; }
}
#include<iostream>
#include<cmath>
#include<ctime>
#include<cstdlib>
#include<windows.h>
using namespace std;
void z()
{
Sleep(100);
}
class Car
{
double fuel;
double speed;
double X;
double Y;
public:
Car(double n, char *type)
{
fuel=n;
speed=120;
}
double Speed()
{
return speed;
}
void Position(double p, double q)
{
X = p;
Y = q;
}
void Move()
{
X=X+(Speed()/3600);
Y=Y+(Speed()/3600);
}
};
int main()
{
Car c(70,"Car");
double x,y;
c.Position(3.2,2.2);
cout<<c.Speed()<<endl;
while(1)
{
c.Move();
c.Position(x,y);
cout<<x<<","<<y<<endl;
z();
}
return 0;
}
I want to show the changes of position in the same line that means in each second the value of position will be updated and show it in the same line replacing the older value but will not create any new line.
I use for_each and mem_fun_ref as a example ,but there are some error in compile ,what's the problem
#include<iostream>
#include<algorithm>
#include<set>
#include<iterator>
using namespace std;
class Tst
{
public:
Tst(int a, string b):n(a),s(b)
{}
bool operator<(const Tst& t)const
{
return this->n < t.n;
}
int GetN()const
{
return n;
}
string GetS()const
{
return s;
}
void SetN(int a)
{
n = a;
}
void SetName(string name)
{
s = name;
}
void Print(void)
{
cout <<"n is:" << n <<"\ts is:" << s << endl;
}
private:
int n;
string s;
};
int main(void)
{
typedef set<Tst> TstSet;
TstSet tst;
tst.insert(Tst(10, "abc"));
tst.insert(Tst(1, "def"));
for_each(tst.begin(), tst.end(), mem_fun_ref(&Tst::Print));
return true;
}
:4200: 错误：对‘(std::mem_fun_ref_t) (const Tst&)’的调用没有匹配，是什么原因
std::set's contained objects are const, so you can only call const functions on them. Your Print function should be marked const.
The function should be const, because std::set only works with const objects
void Print(void)const
{
}
I created the following class
#include "cliques.h"
#include "vector"
#include <iostream>
using namespace std;
cliques::cliques(){
}
cliques::cliques(int i) {
clique.push_back(i);
clique_prob = 1;
mclique_prob = 1;
}
cliques::cliques(const cliques& orig) {
}
cliques::~cliques() {
}
void cliques::addvertex(int i) {
clique.push_back(i);
}
double cliques::getclique_prob() const {
return clique_prob;
}
double cliques::getMaxclique_prob() const {
return mclique_prob;
}
void cliques::showVertices() {
for (vector<int>::const_iterator i = clique.begin(); i !=clique.end(); ++i)
cout << *i << ' ';
cout << endl;
}
vector<int> cliques::returnVector() {
return clique;
}
void cliques::setclique_prob(double i) {
clique_prob = i;
}
void cliques::setMaxclique_prob(double i) {
mclique_prob = i;
}
Here's the header file
#include "vector"
#ifndef CLIQUES_H
#define CLIQUES_H
class cliques {
public:
void addvertex(int i);
cliques();
cliques(int i);
cliques(const cliques& orig);
virtual ~cliques();
double getclique_prob() const;
double getMaxclique_prob() const;
void showVertices();
std::vector<int> returnVector();
void setclique_prob(double i);
void setMaxclique_prob(double i);
private:
float clique_prob;
float mclique_prob;
std::vector <int> clique;
};
#endif /* CLIQUES_H */
I want to create a vector of these objects in order to implement a heap
int main(int argc, char** argv) {
cliques temp(1);
cliques temp1(2);
temp.setclique_prob(0.32);
temp.setclique_prob(0.852);
temp.showVertices();
temp1.showVertices();
vector <cliques> max_heap;
max_heap.push_back(temp);
max_heap.push_back(temp1);
double x =max_heap.front().getclique_prob();
cout<<"prob "<<x<<endl;
cliques y = max_heap.front();
y.showVertices();
//make_heap (max_heap.begin(),max_heap.end(),max_iterator());
//sort_heap (max_heap.begin(),max_heap.end(),max_iterator());
return 0;
}
For reasons unknown to me none of my class functions work properly after i create my vector, meaning that while the following function works as intended
temp.showVertices()
the next one doesn't,
y.showVertices()
You miss implementation for
cliques::cliques(const cliques& orig) {
}
STL vector uses copy constructor inside when you add values to it. As your cliques class does not allocate any memory, you can just remove the copy constructor from the code and compiler will generate one for you.
I am trying to pass a pointer into my classes function, have it incremented, and have the variable retain it's value using pointers. Heres my code, it doesnt increment.
#include "stdafx.h"
#include <iostream>
using namespace std;
class test
{
public:
int addTo();
test(int * currentY);
private:
int y;
};
test::test(int * currentY):
y(*currentY)
{
}
int test::addTo()
{
y++;
return 0;
}
int main ()
{
for (;;)
{
int pointedAt = 1;
int * number = &pointedAt;
test t(number);
t.addTo();
cout <<*number;
char f;
cin >>f;
}
}
This should do it:
#include "stdafx.h"
#include <iostream>
using namespace std;
class test
{
public:
int addTo();
test(int * currentY);
private:
int *y;
};
test::test(int *currentY):
y(currentY)
{}
int test::addTo()
{
++*y;
return 0;
}
int main ()
{
for (;;)
{
int pointedAt = 1;
test t(&pointedAt);
t.addTo();
cout << pointedAt;
}
}
You have to store a pointer to the integer, so it refers to the same address as the original variable.