Discovering C language

#include <stdio.h>
#include <stdlib.h>

int main()
{
    char ch[50];
    char ch1[50];
    int test,i;
    do
    {
        printf ("Donner le premier mot\n");
        scanf ("%s",ch);
        printf ("Donner le deuxieme mot\n");
        scanf ("%s",ch1);
        test=strlen(ch)==strlen(ch1);
    }while (test!=1);
    i=0;
    do
    {
        test=ch[i]==ch1[(strlen(ch)-1)-i];
        i++;
    }while (test==1 && i<strlen(ch));
    if (test==1)
    {
        printf ("Les deux mots sont inverses");
    }
    return 0;
}