C_数据结构_递归A函数调用B函数

# include <stdio.h>

int g(int);
int f(int);

int f(int n)
{
    if (n < )
        printf("haha\n");
    else
        n = f(n-);

    return n;
}

int g(int m)
{
    m = m*;

    return m;
}

int main(void)
{
    int val;

    val = f();
    printf("val = %d\n", val);

    return ;
}

# include <stdio.h>

int f(int n)
{
    n += ;
    return n;
}

int main(void)
{
    int val;

    val = f();    

    return ;
}