// test3：多函数协作（函数调用 + 全局变量）
i32 a;
i32 b;

fn sum() {
    return a + b;
}

fn product() {
    return a * b;
}

fn main() {
    i32 s;
    i32 p;
    a = 3;
    b = 4;
    // s = sum(a);
    s = sum();
    p = product();
    return s + p;
}