程序代码：

#include <stdio.h>
int main(void)
{
    int a[10] = {0, 1, 2, 3, 3, 5, 6, 7, 8, 3};
    int b = 0;

    printf("Please you input the number: ");
    scanf("%d", &b);
    int length = sizeof(a)/sizeof(int);
    for(size_t i = 0, j = 0; i != length; ++i){
        if(b == a[i]){
            ++j;
            printf("The number of %d times it appears in the array is %d\n", j, i+1);
        }
    }
    return 0;
}

[此贴子已经被作者于2020-4-21 15:46编辑过]

程序代码：

#include <stdio.h>
int main(void)
{
    int a[10] = {0, 13, 2, 23, 3, 5, 6, 13, 3, 13};
    int x = 0;
    size_t i, j, k;
    printf("Please you input the number: ");
    scanf("%d", &x);
    int length = sizeof(a)/sizeof(int);
    for(i = 0, j = 0; i != length; ++i){
        if(x == a[i]){
           j = i;
           continue;
        }
    }
    printf("The index of the last element that is the same as x is %d\n", j);
    return 0;
}