A word search is a game where letters of words are hidden in a grid (2D char array), that usually has a rectangular or square shape. The objective of this game is to find and mark all the words hidden inside the grid. The words may be hidden horizontally (left-to-right ), vertically (top-to-bottom ) or diagonally (left-top-to-right-bottom ). Actually you solved this problem for the three cases in HW2.

Now you are asked to write a function that implements reverse horizontal (right-to-left <-- ) search to find out if a given word (a null terminated string) appears reverse horizontally in a given grid (2D array of characters, rows or columns are NOT null terminated). If the word appears reverse horizontally in the grid then your function should return 1 as well as the index values for the beginning row and column numbers (br, bc) of the hidden word in the grid; otherwise, the function returns 0.

Here is an example showing how the function that you will implement in the next page might be used in main( ).

/* suppose std C libs are included here */

#define ROW 2

#define COL 4

/* these numbers will be large in an actual program */

main() {

char g[ROW][COL] = {{'a','b','c','d'}, {'x','y','z','d'}};

char w[128];

int res, br, bc;

printf("Enter the word you want to search in the grid : ");

fgets(w, 127, stdin);

res = reverse_horizantal( g, w, &br, &bc);

/* YOU WILL IMPLEMENT */

if(res==1)

printf("Word %s appears reverse horizontally at (%d, %d) ", w, br, bc);

else

printf("Word %s is not found ", w);

}

/* For example when w is "dzy" the program should print dzy appears reverse horizontally at (1, 3) */

Hint: Suppose the function int substrindex(char *str, char *substr); that you implemented in Question 1 works correctly and available for you to use in this question. Recall that it returns -1 if substr is not in str; otherwise, it returns an index value showing where substr starts in str. This function expects both str and substr to be null terminated strings.

code:

int reverse_horizantal(char g[][COL], char *w, int *br, int *bc ) {