Question

How can I convert a number char in a buffer to an int.

I use:

char *buffer = somebuffer;
int number;
number = int(buffer[i]); // pointer to a number stored as a char 

However, this returns the decimal code (e.g. if buffer[i] = '2', number = 50).

How can I interpret this char number as an int?

Answer 1

You can subtract your char code from the character code for 0 (character codes for numbers are sequential and run from 0 (ascii 48) – 9 (ascii 57)). Be sure to use isdigit first to check the char isn’t outside the range '0' – '9'

int num = 0;
if (isdigit(buffer[i]) {
    num = buffer[i] - '0';
}