#include<stdio.h>
#include<string.h>
#include<conio.h>
#include<stdlib.h>
#define N 10
typedef struct ss
{
    char num[10];
    int s;
}STU;
fun(STU a[],STU*s)
{
    int i;
    *s=a[0];
    for(i=0;i<N;i++)
    {
        if(s->s>a[i].s)
            *s=a[i];
    }
}


void main()
{
    FILE*wf;
    STU a[N]={{"A01",81},{"A02",89},{"A03",66}，{"A04",87}，{"A05",77}，{"A06",90}，{"A07",79}，{"A08",61}，{"A09",80}，{"A10",71}},m;
    int i;
    system("CLS");
    printf("***** The original data *****\n");
    for(i=0;i<N;i++)
        printf("No=%s Mark=%d\n",a[i].num,a[i].s);
    fun(a,&m);
    printf("***** the result*****\n");
    printf("The lowest:%s,%d\n",m.num,m.s);
    wf=fopen("out.dat","w");
    fprintf(wf,"%s,%d",m.num,m.s);
    fclose(wf);
}

STU a[N]={{"A01",81},{"A02",89},{"A03",66}，{"A04",87}，{"A05",77}，{"A06",90}，{"A07",79}，{"A08",61}，{"A09",80}，{"A10",71}},m;
 这句有问题

你这本来就是初始化数组  后面跟个m 干嘛 这就是乱精简代码  还有你这里不知道是哪个逗号有问题 我更改这样就没问题

STU a[10]={{"A01",81},{"A02",89},{"A02",89},{"A02",89},{"A02",89},{"A02",89},{"A02",89},{"A02",89},{"A02",89},{"A02",89}};
    STU m;

还有函数没有声明返回值类型  不知道哪个老师教的  函数这块还是好好再多学习一下

，{"A04",87}，{"A05",77}，{"A06",90}，{"A07",79}，{"A08",61}，{"A09",80}，{"A10",71}
全角“，”符号