求大神帮忙看看，好像是指针用错了，但我找不出错

 #include<stdio.h>
int main() {
    int max(int *a);
    int min(int *b);
    int aver(int *c);
    int a[8];
    printf("please type eight num:");
    for (int i = 0; i < 8; i++) {
        scanf_s("%d", &a[i]);
    }
    printf("max=%d min=%d aver=%d",max(a),min(a),aver(a));
    for (int i = 0; i < 7; i++) {               //冒泡排序
        for (int j = 0; j < 7 - i; j++) {
            int k;
            k = a[j];
            a[j] = a[j + 1];
            a[j + 1] = k;
        }
    }
    for (int i = 0; i < 8; i++) {
        printf("%d", a[i]);
    }
}
//最大值
int max(int *a) {
    int *p;
    for (p = a; p < p + 7; p++) {
        if (*p > *(p + 1)) {
            int k;
            k = *p;
            *p = *(p + 1);
            *(p + 1) = k;
        }
    }
    return a[8];
}
//最小值
int min(int *b) {
    int *p;
    for (p = b; p < p + 7; p++) {
        if (*p <*(p + 1)) {
            int k;
            k = *p;
            *p = *(p + 1);
            *(p + 1) = k;
        }
    }
    return b[8];
}
//平均值
int aver(int*c) {
    int sum = 0, aver;
    for (; c < c + 8; c++) {
        sum += *c;
    }
    aver = sum / 8;
    return aver;
}

#include<stdio.h>
int main() {
    int max(int *a);
    int min(int *b);
    float aver(int *c);
    int a[8];
    printf("please type eight num:");
    for (int i = 0; i < 8; i++) {
        scanf_s("%d", &a[i]);
    }
    printf("max=%d min=%d aver=%f\n",max(a),min(a),aver(a));
    for (int i = 0; i < 7; i++) {               //冒泡排序
        for (int j = 0; j < 7 - i; j++) {//修改
            if(a[j]>a[j+1]){
            int k;
            k = a[j];
            a[j] = a[j + 1];
            a[j + 1] = k;
        }
        }
    }
    for (int i = 0; i < 8; i++) {
        printf("%d ", a[i]);
    }
    printf("\n");
}
//最大值
int max(int *a) {
    int i,k;
    k=a[0];
    for (i=1; i<8; i++) {
        if (a[i]> k) {
            k=a[i];
        }
    }
    return k;
}
//最小值
int min(int *a) {
    int i,k;
    k=a[0];
    for (i=1; i<8; i++) {
        if (a[i]< k) {
            k=a[i];
        }
    }
    return k;
}
//平均值
float aver(int*c) {
    float sum = 0, aver;
    for (int i=0; i<8; i++) {
        sum += c[i];
    }
    aver = sum / 8;
    return aver;
}

还是不知道我写的min和max函数哪里错了