【小白求教】写了个程序，指针有点问题

#include<stdio.h>
#include<stdlib.h>
#define NUM 5
void save(int* p, int n);
void read(int* p, int n);
void menu();
void output(int* p, int num);
void scan(int* p, int num);
int checkLoc(int loc);
int insert(int a[NUM + 1], int N, int b, int c);
int deleting(int a[NUM + 1], int b);
int find(int a[NUM + 1], int x);

int main()
{
    int select;//选项输入
    int flag, index;//标志数字
    int loc, x;//位置和数字
    int t;
    int i;//循环参数
    int a[NUM + 1];
    for (i = 0; i < NUM; i++)
    {
        scanf("%d", &a[i]);//通过键盘给数组赋值
    }

    //read(a,NUM);//通过文件读入数值
    output(a, NUM);//请打印数组
    for (;;)
    {
        menu();
        printf("请输入选项1-5进行选择:\n");
        scanf("%d", &select);
        switch (select)
        {
        case 1:
            while (1)
            {
                printf("请输入待插入一个位置\n");
                scanf("%d", &loc);
                t = checkLoc(loc);
                if (t == 1)//checkLoc函数用来检测插入或删除位置的检测，比如位置不能小于0
                    break;
            }
            printf("请输入一个待插入的数:\n");
            scanf("%d", &x);
            flag = insert(a[NUM + 1], NUM, loc, x);
            output(a, NUM);//请在a数组中的loc位置插入一个值x，成功返回1，不成功返回0
            break;
        case 2:
            while (1)
            {
                printf("请输入待删除一个位置:\n");
                scanf("%d", &loc);
                t = checkLoc(loc);
                if (t == 1)//checkLoc函数用来检测插入或删除位置的检测，比如位置不能小于0
                    break;
            }
            flag = delete(a[NUM + 1], loc);//请在a数组的loc位置删除一个数，成功返回1，不成功返回0
            break;
        case 3:
            index = find(a[NUM + 1], x);//请在a数组中查找x，成功返回x所在下标，不成功返回-1
            break;
        case 4:
            //update(a, loc, x, NUM + 1);
            break;
        case 5:
            exit(0);
        default:
            printf("输入有误，请重新输入");
        }
    }
    save(a, NUM + 1);
}


void save(int* p, int n)
{
    FILE* fp;
    if ((fp = fopen("f:\\ab.txt", "wb+")) == NULL)

    {
        printf("cannot open file ");
        exit(0);
    }

    int  t = fwrite(p, sizeof(int), n, fp);
    printf("t=%d", t);
    fclose(fp);
}

void read(int* p, int n)
{
    FILE* fp;
    if ((fp = fopen("f:\\ab.txt", "rb")) == NULL)
    {
        printf("cannot open file ");
        exit(0);
    }

    int  t = fread(p, sizeof(int), 5, fp);
    int i;
    for (i = 0; i <= n - 1; i++)
    {
        printf("p[i]=%d", p[i]);
    }

    fclose(fp);
}
void menu()
{
    printf("\n\t\t\t\twelcome to the data world!\n");
    printf("\n");
    printf("\t\t\t1、向数组插入数值            2、删除数组的值\n");
    printf("\n");
    printf("\t\t\t3、查找数组元素              4、修改数组的值\n");
    printf("\n");
    printf("\t\t\t5、退出\n");
    printf("\n");
}

void output(int* p, int num)
{
    int i;
    for (i = 0; i <= num - 1; i++)
    {
        printf("%4d", p[i]);
    }
}
void scan(int* p, int num)
{
    int i;
    printf("请给数组赋值：%d个\n", num);
    for (i = 0; i <= num - 1; i++)
    {
        scanf("%d", &p[i]);
    }
}
int checkLoc(int loc)
{
    if (loc < 0 || loc>4)
    {
        printf("输入位置无效\n");
        return 0;
    }
    else
        return 1;
}
int insert(int a[NUM + 1], int N, int b, int c) //添加函数，这个函数有问题?
{
    int i;
    for (i = N; i >= b + 1; i--)
        a[i] = a[i - 1];
    a[b] = c;
    printf("插入数据后的序列为：\n");
    for (i = 0; i <= N; i++)
        printf("%4d", a[i]);
    printf("\n");
}

int deleting(int a[NUM + 1], int b)//删除数组
{
    int i;
    for (i = b; i < NUM; i++)
    {
        a[i] = a[i + 1];
    }
    printf("删除数组后的序列为：\n");
    for (i = 0; i <= NUM; i++)
        printf("%4d", a[i]);
    printf("\n");

}

int find(int a[NUM + 1], int x)
{
    int i;
    for (i = 0; i < NUM; i++)
    {
        if (a[i] == x)
        {
            return i;
        }
    }
    return -1;
}