C Programming Tip on Unsigned Types

Do not use an unsigned type to represent a quantity just because it will be never negative (e.g. age or national_debt).

#include<stdio.h>
main() {
　int negative = -1;
　unsigned positive = 1;
　if(negative < positive)
　　printf("This is what we want.\n");
　if(negative > positive)
　　printf("It's just the semantics.\n");
}

Then guess what the output is?