Correct format specifier for return value of sizeof() in C

Question

I have the following code:

#include

int main()
{
    printf(\"The \'int\' datatype is \\t\\t %lu bytes\\n\", sizeof(int));
    printf(\"The \         


        

Answer 1

Technically, you have undefined behaviour due to mismatched format and data types.

You should use %zu for the type associated with sizeof (which is size_t). For example:

 printf("The 'int' datatype is \t\t %zu bytes\n", sizeof(int));

This is particularly important if you intend to target both 32 and 64 bit platforms.

Reference: http://en.cppreference.com/w/c/io/fprintf