c - 未能在 main 中测试函数

Question

我尝试测试我的 GradeStat 函数，但在突出显示的行中它在 main 中失败：printf("%d", c[0]);.. 它给了我错误：segmentation fault但我不知道为什么..

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

int** GradeStat(int* Grades, int size_grades, int grd_range, int* count_grd, int* avg_grd) {
    const int len = 100/grd_range+1;
    int** collector = malloc(len * sizeof(int*));
    count_grd = calloc(len, sizeof(int));
    avg_grd = calloc(len, sizeof(int));
    size_t i;
    for(i=0; i<size_grades; i++)
        count_grd[Grades[i]/grd_range]++;
    for(i=0; i<len; i++) {
        if (count_grd[i] == 0)
            collector[i] = NULL;
        else
            collector[i] = malloc(count_grd[i] * sizeof(int));
    }
    int** temp = malloc(len * sizeof(int*));
    for(i=0; i<len; i++) {
        temp[i] = collector[i];
    }
    for(i=0; i<size_grades; i++) {
        *(collector[Grades[i]/grd_range]++) = Grades[i];
        avg_grd[Grades[i]/grd_range] += Grades[i]/count_grd[Grades[i]/grd_range];
    }
    for(i=0; i<len; i++) {
        collector[i] = temp[i];
    }
    free(temp);
    return collector;
}

int main() {
    int** arr;
    int grd[8] = {10, 43, 46, 49, 80, 60, 98, 100};
    int* c,a;
    arr = GradeStat(grd, 8, 10, c, a);
    ------>  printf("%d", c[0]);  <-------
    return 0;
}

标签： c