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problem with pointers

yash8087 (13)
#include<iostream>
using namespace std;

void update(int *p,int *q) {
*p=(*p)+(*q);
*q=(*p)-(*q);
}

int main() {
int a, b;
cin>>a;
cin>>b;
update(&a,&b);
cout<<a;
cout<<b;

return 0;
}


i am trying above code it uses concept of pointers but not getting the expected output what wrong here
input
9
5
expected output
14
4
getting output as 115
Moschops (7244)
If you expect the output to be on different lines, you need to output line-endings, such as endl

I expect the output of your code to be 149, and that's what I see: http://ideone.com/oyaz8y

Note that in the function update, when you are assigning a new value to q, you are using the value of p that you already changed on the previous line. The calculation is not q=9-4 , but is q=15-4
Last edited on
yash8087 (13)
how can i get the expected ans by
applying the pointers concept?
AbstractionAnon (6954)
Since you want the value of p before you change it, you're going to have to use a temporary. 

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#include<iostream>
using namespace std;

void update(int *p,int *q) 
{   int oldp = *p;
    *p = oldp + (*q);
    *q = oldp - (*q);
}

int main() 
{   int a, b;
    cin>>a;
    cin>>b;
    update(&a,&b);
    cout<<a << endl;
    cout<<b << endl;
    system ("pause");
    return 0;
}
 
9
5
14
4
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