How to convert an int to string in C?

Question

How do you convert an int (integer) to a string? I\'m trying to make a function that converts the data of a struct into a string to save it in a fi

Answer 1

The short answer is:

snprintf( str, size, "%d", x );

The longer is: first you need to find out sufficient size. snprintf tells you length if you call it with NULL, 0 as first parameters:

snprintf( NULL, 0, "%d", x );

Allocate one character more for null-terminator.

#include  
#include 

int x = -42;
int length = snprintf( NULL, 0, "%d", x );
char* str = malloc( length + 1 );
snprintf( str, length + 1, "%d", x );
...
free(str);

If works for every format string, so you can convert float or double to string by using "%g", you can convert int to hex using "%x", and so on.