how to store a masked array - c

Question

i have been asked to code a memory game, with some specifics, where the reveled letter shows the first time then, if the user in the 2nd prompt guesses the corresponding matching spot, the board should stay like that until the user finishes the game (by guessing all of the correct matching spots), heres an example with a 2x2 grid
Your program:
* *
* *
Enter a pair of integers in the range [1, 2]
Player: 1 1
Your program:
A *
* *
(then it clears the screen and displays)
* *
* *
Enter another pair of integers in the range [1, 2]
Player: 2 1
Your program:
* *
C *
(then it clears screen and displays)
* *
* *
Enter a pair of integers in the range [1, 2]
Player: 1 2
Your program:
* C
* *
(then it clears screen and displays)
* *
* *
Enter another pair of integers in the range [1, 2]
Player: 2 1
Your program:
* *
C *
(then it clears the screen and displays)
* C
C *
Enter a pair of integers in the range [1, 2]
Player: 1 1
Your program:
A C
C *
(then it clears the screen and displays)
* C
C *
Enter another pair of integers in the range [1, 2]
Player: 1 1
Your program:
A C
C *
(then it clears the screen and displays)
* C
C *
Enter a pair of integers in the range [1, 2]
Player: 1 1
Your program:
A C
C *3
(then it clears the screen and displays)
* C
C *
Enter another pair of integers in the range [1, 2]
Player: 2 2
Your program:
A C
C A
CONGRATULATIONS. YOU SUCCEEDED
i need a 4x4, i understand how to show the correct matches but i cannot seem to store the new board, so the user sees the most current board, i cant wrap my head around it....
char board[4][4] = { {'A','B','A','D'},{'C','E','H','G'},{'B','D','G','C'},{'F','H','F','E'} };
int i, j, row, column, row2, column2;
char boardmatch[4][4];
int tempX,tempY;
for(tempX = 0; tempX < 4; tempX++){
for(tempY = 0; tempY < 4; tempY++){
boardmatch[tempX][tempY] = 0;
}
}
for (i=0; i < 4 ; i++){
for (j=0; j<4; j++){
printf("* ");
}
printf("\n");
}
do {
printf("\nEnter a pair of integers in the range [1, 4]: ");
scanf("%d %d", &row, &column);
row--;
column--;
printf("\n");
for (i=0; i < 4 ; i++){
for (j=0; j < 4 ; j++){
if ( i == row && j == column){
printf("%c ", board[row][column]);
}else{
printf("* ");
}
}
printf("\n");
}
printf("\n");
system("pause");
system("cls");
for (i=0; i < 4 ; i++){
for (j=0; j<4; j++){
printf("* ");
}
printf("\n");
}
printf("\nEnter another pair of integers in the range [1, 4]: ");
scanf("%d %d", &row2, &column2);
row2--;
column2--;
printf("\n");
for (i=0; i < 4 ; i++){
for (j=0; j < 4 ; j++){
if (i == row2 && j == column2){
printf("%c ", board[row2][column2]);
}else{
printf("* ");
}
}
printf("\n");
}
system("pause");
system("cls");
if(board[row][column]==board[row2][column2]){
boardmatch[row][column] = 1;
boardmatch[row2][column2] = 1;
}
for (i=0; i < 4 ; i++){
for (j=0; j<4; j++){
if (boardmatch[i][j] == 1){
printf("%c ", board[row2][column2]);
}else{
printf("* ");
}
}
printf("\n");
}
printf("\n");
system("pause");
system("cls");
}while(1);
system("PAUSE");
return 0;
}

Answer 1

You need another array for the board.
It just holds a bit for each cell, meaning 'found' or 'turned'.
Use that (and the original board) to display the board.
Only show the cells that have been found/turned.
For the players turns, when some cells might be turned back, just remember which cell was turned so you can flip it back to unfound/unturned. This array starts out as all unturned and the game finishes when they are all turned.
(You can use a struct to put this all in one array as well.)

Answer 2

The problem is in these lines (fix already applied).
if (boardmatch[i][j] == 1)
{
printf("%c ", board[i][j]);
}
It should show the correct value if it has been matched before. Not the ones under row2, column2
Also, here's an alternative on what you're doing, storing the previous values of row and column as row_old and column_old.
#include <stdio.h>
// Prints the matrix
void board_print(char board[4][4], char boardmatch[4][4], int revealRow, int revealColumn, int revealRow2, int revealColumn2)
{
int row, col;
printf(" 0 1 2 3\n");
// Printing code
for (row=0; row < 4 ; row++)
{
printf ("%d ", row);
for (col=0; col<4; col++)
{
// Print the value if there's a board match
// or there's a revealRow/revealColumn
if (boardmatch[col][row] == 1
|| (row == revealRow && col == revealColumn)
|| (row == revealRow2 && col == revealColumn2))
{
printf("%c ", board[col][row]);
}
else
{
printf("* ");
}
}
printf("\n");
}
}
// Clears board
void board_clear(char board[4][4])
{
int i,j;
for(i = 0; i < 4; i++)
{
for(j = 0; j < 4; j++)
{
board[i][j] = 0;
}
}
}
// Main game loop
void game_loop()
{
char board[4][4] = { {'A','B','A','D'},{'C','E','H','G'},{'B','D','G','C'},{'F','H','F','E'} };
int row, column, row_old=-1, column_old=-1;
char boardmatch[4][4];
board_clear(boardmatch);
// Reveal the matrix
board_print(board, boardmatch, -1, -1, -1, -1);
do
{
// Ask for input
printf("\n[column row]: ");
fflush(stdin);
scanf("%d %d", &column, &row);
// Adjust the values
// Check the previous value
if (row_old == -1 || column_old == -1)
{
// There was nothing stored
// Store the previous values
row_old = row;
column_old = column;
// Print only the selected value
board_print(board, boardmatch, row, column, -1, -1);
}
else
{
// There was something stored
// Check if he did it
if (board[column][row] == board[column_old][row_old])
{
// You did it! Store as matched
boardmatch[column][row] = 1;
boardmatch[column_old][row_old] = 1;
// Present the result to the user
board_print(board, boardmatch, row, column, -1, -1);
printf("Match!\n");
}
else
{
// Nope, you didn't
// Present the two items marked (old and selected)
board_print(board, boardmatch, row, column, row_old, column_old);
printf("YOU SUCK!\n");
}
// Now print the matrix with the selected values
// Finally, kill the previous values
row_old = -1;
column_old = -1;
}
// (Check the boardmatch if every value is 1, and break if it does)
} while (1);
}
int main(int argc, const char * argv[])
{
game_loop();
return 0;
}
The key here, is that the row_old and column_old acts as the check for the items, as much as it acts for a flag for the game.
Whenever it's -1, it means that the previous match has not been made, and when it stores a value, it represents the previous match.
I also suggest as an improvement and/or lesson, modify the code using the structs:
#import <stdbool.h>
typedef struct
{
char value;
bool matched;
}tile;
typedef struct
{
int row, col;
}coordinate;