you havent stated the problem clearly but i think that you want the user to input any word, so that you can search the array x, to see if it contains the word.. rite..?
lets see,
1. get the y[0] and check with the x[i]
2. if you find it, do the following
i. check the y[1] with x[i+1] and if it matches check the next untill you come to y[j] == NULL
3. go to next x ( i++ ) and repeat the process....