一个结构体内含有 学号 姓名 成绩

刚出炉的,你试试看:
#include <stdio.h>
#define N 2
struct stu
{
long num;
char name[10];
int score;
};
main()
{
struct stu s[N];
int i;
int score;
printf("input the information of students\n");
for(i=0;i<N;i++)
scanf("%ld%s%d",&s[i].num,s[i].name,&s[i].score);
printf("\ninput the score for searching\n");
scanf("%d",&score);
for(i=0;i<N;i++)
if(s[i].score==score)
printf("number:%ld\nname:%s\n",s[i].num,s[i].name);
}

struct student
{
int num;
char name[30];
int score;
};

struct stu
{
int num;
char name[];
int score;
}student;