数组的运用，删除数组为什么删除不了？

    #include "stdio.h"
    int data[100];
    int n=0;

    void main()
    {
    int c;
    while(1)
    {
    printf("1: add number\n");
    printf("2: delete number\n");
    printf("3: print\n");
    printf("0: exit\n");
    c=scanf("%d", &c);
    switch (c)
    {
    case 0: return;
    case 1:
    int i;
    scanf("%d", &i);
    data[n++]=i;
    break;
    case 2:
    n--;
    break;
    case 3:
    for(i=0;i<n;i++)
    printf("%d ",data[i]);
    printf("\n");
    break;
    }
    }
    }