Know Your Integers

Standard Data Types: size_t (1)

Sizes are everywhere

• Number of bytes in an allocated chunk of memory

• Number of elements in an array

• Number of microseconds until timer runs off

• Result of the strlen() function

• Result of the sizeof operator

This is what size_t is there for:

• Nobody has to worry about signedness (sizes simply don’t become negative)

• ⟶ adds clarity

#include <unistd.h>

Standard Data Types: size_t (2)

Consequences

• None (except for readability)

• (GCC) -Wsign-compare, -Wtype-limits, …

  • lots of warnings when mixing

  • consider -Wextra

• ⟶ Correctness (up to a certain extent)

Find at least two Bugs!

size_t sum(int set[], size_t size)
{
    size_t sum = 0;
    while (size-- >= 0)
        sum += set[size];
    return sum;
}