Thingy.c

#include <stdio.h>

int main(void) {
    int fahr, cels;
    int lower, upper, step;

    lower = 0;
    upper = 300;
    step = 20;

    fahr = lower;
    while (fahr <= lower) {
        cels = 5 * (fahr-32) / 9;
        printf("%d\t%d\n", fahr, cels);
        fahr = fahr + step;
    }
    return 0;
}