char variable and if statement error C++

2017-05-26

An answer to this question on Stack Overflow.

Question

I have the following for loop:

string temp;
int responseInt[10][10] = { {0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0}};
for (int i = 0; i < numberPros; i++)
{
	for (int j = 0; j < numberRes; j++)
	{
		cout << "Is " << process[i] << " holding (h), requesting (r), or doing nothing (n) to " << resources[j] << " ?: ";
		cin >> temp;
		if (temp == 'n')
			responseInt[i][j] = 0;
		else if (temp == 'h')
			responseInt[i][j] == -1;
		else if (temp == 'r')
			responseInt[i][j] == 1;
	}
}

However, it's like if the if statements are ignored, since the default values for responseIntare never changed, even if I type h or r or n.

I already tried with strings, but the same thing happens.

Any help would be appreciated.

Answer

This works:

#include <string>
#include <iostream>
using namespace std;
int main(){
    string temp;
    int responseInt[10][10] = { {0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0}};
    int numberPros = 2;
    int numberRes  = 10;
    for (int i = 0; i < numberPros; i++)
    {
        for (int j = 0; j < numberRes; j++)
        {
            cout << "Is " << i << " holding (h), requesting (r), or doing nothing (n) to " << j << " ?: ";
            cin >> temp;
            if (temp == "n")
                responseInt[i][j] = 0;
            else if (temp == "h")
                responseInt[i][j] == -1;
            else if (temp == "r")
                responseInt[i][j] == 1;
        }
    }
}

Your cin>>temp is reading a string, so it is best to compare it against strings by using double quotes (e.g. "r") rather than single quotes (e.g. 'r').

Note that I've had to include a bunch of extra code to make things compile. This should have been in your question, as a minimum working example (MWE).