The assignment is to write a word searching program. The program reads from file
ID: 669972 • Letter: T
Question
The assignment is to write a word searching program. The program reads from file “square” an NxN square filled with letters, and a list of words. There are words buried in the square, either left to right, right to left, top to bottom, bottom to top, diagonally, and so on. This is best explained by an example data file and the output. Suppose that this is the input file:
T
A
E
D
Q
Q
Z
H
P
N
I
U
C
K
E
W
D
I
V
U
X
O
F
C
B
P
I
R
G
K
N
R
T
B
R
B
EXIT
THE
QUICK
BROWN
FOX
Before explaining the program, let me describe the data in more detail. For reading in the square, there is a space after each letter in the square, including the last letter in each row. Looking at the first row, it is “T”, then space, then “A”, then space, etc. and there is a space and a newline character after the last “Q”. By reading the first line of the data, we can tell that this will be a six-by-six square. With respect to the words, they are just a word followed immediately by a newline character. The words will not contain spaces, numbers, etc.
This is a word searching problem. The words such as “EXIT” are contained in the square, oriented in one of eight ways, including left to right, right to left, diagonally down, etc. The output of the program should be the puzzle with the non-used letters removed. Thus, only the words found are printed. The output should be printed exactly like the input square, but with blanks replacing those letters that are never contained within a word.
Here is the output from the above input file:
T
Q
H
N
U
E
W
I
X
O
F
C
I
R
K
T
B
The output must be properly formatted. There should be no blank lines before or after the puzzle and each row of the puzzle is followed by a space and then a newline. So in the example above, there WOULD be a space after the Q in the first row of the solution, there is also a space after the space in the last row.
The square will never be larger than 50 by 50, so you can declare an array of that size or dynamically allocate space. The words will never be longer than the width of the square - six in this example.
Program should be in C
T
A
E
D
Q
Q
Z
H
P
N
I
U
C
K
E
W
D
I
V
U
X
O
F
C
B
P
I
R
G
K
N
R
T
B
R
B
Explanation / Answer
answer:
#include <ctype.h>
#include <stdio.h>
#include <string.h>
static int prompt_for(char *buffer, size_t buflen);
static int search_direction(char array[18][18], char *string, int length, int X, int Y, int dx, int dy);
static int search_from(char array[18][18], char *string, int length, int X, int Y);
int main(void)
{
int X, Y, length;
char array[18][18], string[50];
printf("WORDSEARCH SOLVER - PRESS CTRL-C TO QUIT ");
FILE *wsch = fopen("wrdsearch.txt", "r");
if (!wsch)
{
printf("Error! File did not open. ");
return 1;
}
for (Y = 0; Y < 18; Y++)
{
for (X = 0; X < 18; X++)
{
fscanf(wsch, " %c", &array[Y][X]);
array[Y][X] = toupper(array[Y][X]);
}
}
fclose(wsch);
printf(" ");
for (X = 0; X < 18; X++)
printf("%-2d", X);
printf(" ______________________________________ ");
for (Y = 0; Y < 18; Y++)
{
printf("%-2d|", Y);
for (X = 0; X < 18; X++)
printf("%c ", array[Y][X]);
printf(" ");
}
while ((length = prompt_for(string, sizeof(string))) != EOF)
{
printf("Searching for: [%s] ", string);
int count = 0;
for (Y = 0; Y < 18; Y++)
{
for (X = 0; X < 18; X++)
{
if (array[Y][X] == (string[0]) && search_from(array, string, length, X, Y))
count++;
}
printf("Found %s %d times ", string, count);
}
printf(" ");
return 0;
}
static int prompt_for(char *buffer, size_t buflen)
{
printf(" Please enter the word to be searched: ");
if (fgets(buffer, buflen, stdin) == 0)
return EOF;
size_t length = strlen(buffer);
if (buffer[length-1] == ' ')
buffer[--length] = '';
if (length == 0)
return EOF;
for (size_t i = 0; i < length; i++)
buffer[i] = toupper(buffer[i]);
return length;
}
static int search_from(char array[18][18], char *string, int length, int X, int Y)
{
struct yx { int dy; int dx; } directions[] =
{
{ +1, 0 }, { -1, 0 }, { +1, +1 }, { -1, +1 },
{ 0, +1 }, { 0, -1 }, { -1, -1 }, { +1, -1 },
};
enum { num_directions = sizeof(directions) / sizeof(directions[0]) };
int count = 0;
for (int i = 0; i < num_directions; i++)
{
if (search_direction(array, string, length, X, Y, directions[i].dx, directions[i].dy))
count++;
}
return count;
}
static int search_direction(char array[18][18], char *string, int length, int X, int Y, int dx, int dy)
{
for (int i = 1; i < length; i++)
{
int x = X + i * dx;
int y = Y + i * dy;
if (x < 0 || x >= 18 || y < 0 || y >= 18)
return 0;
if (array[y][x] != string[i])
return 0;
}
printf("Found word %s starting at (%d,%d) to (%d,%d) ",
string, Y, X, Y + (length - 1) * dy, X + (length - 1) * dx);
/* Validating search! */
char *pad = "";
for (int i = 0; i < length; i++)
{
int x = X + i * dx;
int y = Y + i * dy;
printf("%s%c (%d,%d)", pad, array[y][x], y, x);
pad = ", ";
}
putchar(' ');
return 1;
}
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