위에 친구가 짠 거 보고 수정해봄. ㅎㅎ

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

int main()
{
        char str[100] = "";
        int len, i;
        int num[10];
        int temp;

        for(i = 0; i < 10; i++)
        {
                num[i] = 0;
        }
        
        printf("숫자 입력: ");
        scanf("%s", str);

        len = strlen(str);

        for(i = 0; i < len; i++)
        {
                if(str[i] < '0' || str[i] > '9')
                {
                        printf("입력오류: %c가 입력됨\n", str[i]);
                        return 0;        
                }
                else
                {
                        temp = str[i] - 48;
                        num[temp]++;
                }
        }

        printf("숫자: 0 1 2 3 4 5 6 7 8 9\n");
        printf("반복: ");
        
        for(i = 0; i < 10; i++)
                printf("%d ", num[i]);

        printf("\n");

        return 0;
}