vowels count

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

int main()
{
    char str_in[100],vowels[5][5];
    int len,i,j,tmp;

    for(i=0;i<5;i++)
    {
        vowels[i][0] = "aeiou"[i];
        vowels[i][1] = '0';
    }

    printf("Enter your string (number of character has to be less than 100): ");
    scanf("%s",str_in);

    len = strlen(str_in);
    printf("Length of the string entered is %d\n",len);

    for(i=0;i<len;i++)
    {
        for(j=0;j<5;j++)
            if(str_in[i]==vowels[j][0])
            {
                tmp = (int)vowels[j][1];
                tmp++;
                vowels[j][1] = (char)tmp;
            }
    }

    for(i=0;i<5;i++)
    {
        printf("%c : %c\n",vowels[i][0],vowels[i][1]);
    }

    return 0;
}