Rotating values between 3 variables using pointer in C++

Question

I have the following code:

int main(){
    int a,b,c;
    cout<<"Enter a: ";
    cin>>a;
    cout<<"Enter b: ";
    cin>>b;
    cout<<"Enter c: ";
    cin>>c;
    int temp;
    int *aPtr = &a, *bPtr = &b, *cPtr = &c;
    int *tempPtr = &temp;
    *tempPtr = *aPtr;
    *aPtr = *bPtr;
    *bPtr = *cPtr;
    *cPtr = *tempPtr;
    cout<<a<<b<<c<<"\n";
    system("pause");
    return 0;
}

Input:

2 3 4

Output

3 4 2

Expected Output

4 2 3

I am using the same logic of swapping values. What am I doing wrong?

Thank you!

Answer 1

You are getting output according to what code you have written. Correct logic for rotation in this case would be:-

int temp;
int *aPtr = &a, *bPtr = &b, *cPtr = &c;
int *tempPtr = &temp;
*tempPtr = *cPtr;
*cPtr = *bPtr;
*bPtr = *aPtr;
*aPtr = *tempPtr;

Just go sequentially. Like first store value of c then shift a and b and then restore a so that it would be easy for you to generalize this.

Answer 2

You are rotating the numbers to the left while you need to rotate the numbers to the right. So when you rotate to the left you need to preserve the value of a because it will be the first that will be overwritten. If you want to rotate to the right then you have to preserve the value of c because it will be the first that will be overwritten.

So you need to write

*tempPtr = *cPtr;
*cPtr = *bPtr;
*bPtr = *aPtr;
*aPtr = *tempPtr;