Selection sort algorithm, written from scratch in C. Using recursion and swap without a temp variable. The swap algorithm:

    a = a + b; // The sum will be the same in both cases, so we use it instead of a temp variable.
    printf("a as a sum: \n", a);
    b = a - b; // b now has the original value of a.
    printf("b with value of a: \n", b);
    a = a - b; // The sum minus the new value of b.

Compile with GCC:

gcc -g -O0 selection_sort.c -o selection sort

Compile with clang:

clang -g -O0 selection_sort.c -o selection sort

where -g is for debugging and -O0 is for no optimization.