用C++写一个成绩管理系统，需要的功能有导入成绩，导出成绩，排名等次，查询学生成绩

好的，这个问题可以回答。以下是一个简单的成绩管理系统的代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_STUDENTS 100

struct student {
    char name[20];
    int score;
};

struct student students[MAX_STUDENTS];
int num_students = 0;

void import_scores(char *filename) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Error: could not open file %s\n", filename);
        return;
    }

    char line[100];
    while (fgets(line, sizeof(line), fp)) {
        char *name = strtok(line, ",");
        int score = atoi(strtok(NULL, ","));
        if (name != NULL) {
            strcpy(students[num_students].name, name);
            students[num_students].score = score;
            num_students++;
        }
    }

    fclose(fp);
}

void export_scores(char *filename) {
    FILE *fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("Error: could not open file %s\n", filename);
        return;
    }

    for (int i = 0; i < num_students; i++) {
        fprintf(fp, "%s,%d\n", students[i].name, students[i].score);
    }

    fclose(fp);
}

void sort_students() {
    for (int i = 0; i < num_students; i++) {
        for (int j = i + 1; j < num_students; j++) {
            if (students[i].score < students[j].score) {
                struct student temp = students[i];
                students[i] = students[j];
                students[j] = temp;
            }
        }
    }
}

void print_students() {
    printf("Name\tScore\n");
    for (int i = 0; i < num_students; i++) {
        printf("%s\t%d\n", students[i].name, students[i].score);
    }
}

int main() {
    import_scores("scores.txt");
    sort_students();
    print_students();
    export_scores("sorted_scores.txt");
    return 0;
}

这个程序可以从一个名为 "scores.txt" 的文件中导入学生的成绩，然后按照成绩从高到低排序，并输出到屏幕上。最后，它还可以将排序后的成绩导出到一个名为 "sorted_scores.txt" 的文件中。