No conversion from “const char” to “int”

Question

The following is the problem code.

#include 
#include 
using namespace std;

void convertToUppercase(char *);

int main()
{
    cha         


        

Answer 1

You are trying to compare a char to a char const* (well, really a char const[2] but that's just a detail). You probably meant to use

while (*sPtr != '\0')

or

while (*sPtr)

Note that your use of islower() and toupper() isn't guaranteed to work: the argument to these functions has to be positive but char may have negative values. You need to first convert the char to unsigned char:

toupper(static_cast(*sPtr))

The test for islower() isn't needed: on non-lower chars toupper() just returns the argument. Omitting the trst is improving the oerformance.