Why cant i use a character as a condition in a while loop?-CodePudding

#include <iostream>

using namespace std;

int main()
{
char sum[100],x[100];


while(x != '=' )
{
cout << "\n Enter number : ";
cin >> x;
sum=sum x;
}   
cout << sum;
return 0;
}

having trouble creating a program where users can input as many numbers to sum up and will only end when they input '='.i cant seem to get this to work when i input the character '=' as the error, invalid operands of types 'char [100]' and 'char [100]' to binary 'operator ', pops up

CodePudding user response：

You may be mistaken with the type the variable x is. x is defined as a char array with the line char x[100] so in order to see the values inside you need to specify an index such as x[49] to get the 50th element which in your case would be the char value you wish to compare to "=".

A for loop may be useful as well to figuring out your problem.

CodePudding user response：

As the comment said, x is not a char but an array of char
I suggest using strcmp function, if the value returned is different than 0 then they are different
Syntax : int strcmp(const char* firstString, const char* secondString)

if(strcmp(x,"=")!= 0)

CodePudding user response：

If the goal is to check whether the user typed the single character '=', all you need to do is look for it:

while (x[0] != '=')
    // body of the loop

That works because x is an array of char; when you read into an array of char the characters are inserted into the array in the order in which they are encountered. So if the user types just plain '=' that will be the first character in the array, i.e., x[0].

Note, however, that the array x has not been initialized, so the first time through the loop, the value of x[0] is indeterminate. That also has a simple fix:

char x[100] = "";

There's no reason to go to more complex solutions like strcmp or std::string for this part of the code.