C program to sum two integers

input:
 stdin 0 -> progname :: string
 stdin 1 -> x :: string
 stdin 2 -> y :: string

output:
 stdout -> x + y :: string

programming language:
 C99

considerations:
 security paranoid programming

stdin 0 is a *nix thing. Now stop acting like a little girl, get with the program, and use the standard stdin. Ie...

FILE *stidn;

Or better yet, use a real programming language like BASIC.