用C语言表示：假设百分制课程成绩和4分制绩点对应计算方法如下： 90-100 4.0 ; 85-89 3.7 ; 82-84 3.3 ; 78-81 3.0 ; 75-77 2.7 ; 72-74 2.3 ; 68-71 2.0 ; 64-67 1.5 ; 60-63 1.0 ; 60分以下0 学分加权平均绩点为：[（学分1* 绩点1）+（学分2* 绩点2）...]/(学分1+学分2...) 输入若干个学生学号（4位数字）和若干门课的百分制成绩和对应学分，按照学生的学分加权平均绩点倒序输出学号和加权平均绩点。以*为结束 输入格式: 学号 百分制成绩 学分 每行一个，以-1为结束记号。 输出格式: 按平均绩点从高到低输出： 学号 平均绩点，每行一个，绩点保留2位小数。

好的，以下是一个基本的实现，你可以根据需要进行修改：

#include <stdio.h>

int main() {
    int num, score, credit, total_credit = 0;
    float point, total_point = 0.0;
    printf("请输入学号、成绩和学分，每行一个，以-1为结束记号：\n");
    scanf("%d", &num);
    while (num != -1) {
        scanf("%d%d", &score, &credit);
        if (score >= 90 && score <= 100) {
            point = 4.0;
        } else if (score >= 85 && score <= 89) {
            point = 3.7;
        } else if (score >= 82 && score <= 84) {
            point = 3.3;
        } else if (score >= 78 && score <= 81) {
            point = 3.0;
        } else if (score >= 75 && score <= 77) {
            point = 2.7;
        } else if (score >= 72 && score <= 74) {
            point = 2.3;
        } else if (score >= 68 && score <= 71) {
            point = 2.0;
        } else if (score >= 64 && score <= 67) {
            point = 1.5;
        } else if (score >= 60 && score <= 63) {
            point = 1.0;
        } else {
            point = 0.0;
        }
        total_credit += credit;
        total_point += point * credit;
        scanf("%d", &num);
    }
    printf("按平均绩点从高到低输出：\n");
    printf("学号 平均绩点\n");
    while (total_credit > 0) {
        printf("%d %.2f\n", num, total_point / total_credit);
        total_credit = 0;
        total_point = 0.0;
        scanf("%d", &num);
        while (num != -1) {
            scanf("%d%d", &score, &credit);
            if (score >= 90 && score <= 100) {
                point = 4.0;
            } else if (score >= 85 && score <= 89) {
                point = 3.7;
            } else if (score >= 82 && score <= 84) {
                point = 3.3;
            } else if (score >= 78 && score <= 81) {
                point = 3.0;
            } else if (score >= 75 && score <= 77) {
                point = 2.7;
            } else if (score >= 72 && score <= 74) {
                point = 2.3;
            } else if (score >= 68 && score <= 71) {
                point = 2.0;
            } else if (score >= 64 && score <= 67) {
                point = 1.5;
            } else if (score >= 60 && score <= 63) {
                point = 1.0;
            } else {
                point = 0.0;
            }
            total_credit += credit;
            total_point += point * credit;
            scanf("%d", &num);
        }
    }
    printf("*\n");
    return 0;
}