#include <stdio.h>

​

int main()

{

    int i,k;

    char arr[50];

    printf("Enter char: ");

    gets(arr);

    k=strlen(arr);

    for(i=0;i<k;++i){

        if(arr[i]=='a'||arr[i]=='e'||arr[i]=='i'||arr[i]=='o'||arr[i]=='u'||arr[i]=='A'||arr[i]=='E'||arr[i]=='I'||arr[i]=='O'||arr[i]=='U'){

            printf("_");

        }

        else{

            printf("%c",arr[i]);

        }

    }

}