CODEWITHSUNDEEP
c++
Mustafa
Mustafa

Reputation: 129

std::cin of char causing infinite loop

I've used the cout statement after the cin's before the switch to determine that I'm having a problem with the second number and the character op and for some reason I get into an infinite loop!!! I have a feeling that I'm making a small mistake in the syntax but I cant figure out what is it.

#include<iostream>
using namespace std;
int main()
{
    float a, b;
    char op, ans;
    do {
    cout << "Enter first number, operator, second number: ";
    cin >> a;
    cin >> b;
    cin >> op;
    cout << "first number is: " << a << "second number is: " << b << "operator is: " << op;
    switch (op) {
    case '/':
        cout << "answer = " << a / b << endl;
        break;
    case '*':
        cout << "answer = " << a * b << endl;
        break;
    case '+':
        cout << "answer = " << a + b << endl;
        break;
    case '-':
        cout << "answer = " << a - b << endl;
        break;
    }
    cout << "again? Y/N";
    cin >> ans;
    } while (ans != 'N' || ans != 'n');

    cout << endl;
    system("pause");
    return 0;
}

Upvotes: 0

Views: 544

Answers (3)

user1662206
user1662206

Reputation:

You need to change from this line:
cin >> a;
cin >> b;
cin >> op;

to this one:
cin >> a;
cin >> op;
cin >> b;

Upvotes: 1

user1508519
user1508519

Reputation:

You want your condition to be:

} while (ans != 'N' && ans != 'n');

It can't not be 'N' and 'n' simultaneously. If that were the case, the world would probably disappear into a vortex of doom.

Upvotes: 4

JGroven
JGroven

Reputation: 613

ans will ALWAYS not equal EITHER n or N. Your OR condition is always going to pass as true. Try switching this to 

    while(ans == 'Y' || ans == 'y')

Upvotes: 6

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