c语言问题，希望得到解决

Question

#include<stdio.h>
void fun(float *s,int n)
{
    int i,m;
    for(s=0,i=1;i<=n;i++)
    {
        if(i%2==0)m=-1;
        else m=1;
        s=s+m/(2*i-1);
    }
}
int main()
{
    int n;
    float m;
    scanf("%d",&n);
    fun(m,n);
    printf("s=%d\n",m);
    return 0;
}

然后就会出现这样的问题
Compile Error（编译出错） temp.cpp: In function 'int main()':
temp.cpp:17:9: error: cannot convert 'float' to 'float*' for argument '1' to 'void fun(float*, int)'
fun(m,n);
^

Answer 1

#include <stdio.h>
void fun(float *s, int n)
{
    int i;
    float m;
    for (i = 2; i <= n+1; i++)
    {
        if (i % 2 == 0)
            m = -1;
        else
            m = 1;
        *s = *s + m / (2 * i - 1);
    }
}
int main()
{
    int n;
    float m = 1;
    scanf("%d", &n);
    fun(&m, n);
    printf("s=%f\n", m);
    return 0;
}