结构指针应用例题

/*修改学生成绩，结构指针作为函数参数*/
#include <stdio.h>
struct student
{
    int num;
    char name[10];
    int computer, english, math;
    double average;
};
int update_score(struct student *p, int n, int num, int course, int score);
int main(void)
{
    int course, i, n, num, pos, score;
    struct student students[50];

    printf("Input n:");
    scanf("%d", &n);
    for (i = 0; i < n; i++)
    {
        printf("Input the info of No.%d:
", i + 1);
        printf("number:");
        scanf("%d", &students[i].num);
        printf("name:");
        scanf("%s", students[i].name);
        printf("math score:");
        scanf("%d", &students[i].math);
        printf("english score:");
        scanf("%d", &students[i].english);
        printf("computer score:");
        scanf("%d", &students[i].computer);
    }

    printf("Input the number of the students to be updated:");
    scanf("%d", &num);
    printf("Choice the course:1.math 2.english 3.computer:");
    scanf("%d", &course);
    printf("Input the new score:");
    scanf("%d", &score);

    pos = update_score(students, n, num, course, score);

    if (pos == -1)
    {
        printf("Not found!
");
    }
    else
    {
        printf("After update:
");
        printf("%d	%d	%d	%d
", students[pos].num, students[pos].math, students[pos].english, students[pos].computer);
    }

    return 0;
}
int update_score(struct student *p, int n, int num, int course, int score)
{
    int i, pos;
    for (i = 0; i < n; i++, p++)
    {
        if (p->num == num)
        {
            break;
        }
    }
    if (i < n)
    {
        switch (course)
        {
        case 1:
            p->math = score;
            break;
        case 2:
            p->english = score;
            break;
        case 3:
            p->computer = score;
            break;
        }
        pos = i;
    }
    else
    {
        pos = -1;
    }

    return pos;
}