int main(void) {
char buffer[1024];
while (fgets(buffer, 1024, stdin)) {
    if ((strcasecmp(buffer,"a")) == 0) {
        aMethod();
        }
    if ((strcasecmp(buffer, "b")) == 0) {
        bMethod();
        }
    }
}

buffer[strcpsn(buffer,"n")]=0;