Comparison Error in C : Pointer vs. Integer

When attempting to compile a simple function from Bjarne Stroustrup's C book, third edition, developers may encounter the compile time error:

error: ISO C   forbids comparison between pointer and integer

This issue arises when comparing a pointer with an integer. In the provided code:

#include 
#include 
using namespace std;
bool accept()
{
    cout > answer;
    if (answer == "y") return true;
    return false;
}

The error appears in the if statement where answer is compared to a string literal ("y"). Since answer is a character variable, it must be compared to a character constant.

Solution

There are two solutions to this issue:

1. Use a string Variable:
   Declare answer as a string type instead of char. This will allow you to compare answer to a string literal correctly:

   string answer;
   if (answer == "y") return true;

2. Use Character Constant:
   Instead of comparing answer to a string literal, use a character constant enclosed in single quotes:

   if (answer == 'y') return true; // Note single quotes for character constant

Both methods effectively resolve the error by ensuring that the comparison is between compatible types.