nudt-compiler-cpp/test/test_case/case_lab3_1/recursion.sy

int fib(int n) {
    if (n <= 1) return n;
    return fib(n-1) + fib(n-2);
}
int main() {
    int n = 6;
    putint(fib(n));
    putch(10);
    return 0;
}