cornstar94 - 1 year ago 203
C Question

# CS50 Pset3 function "Won"

I am at the last part of the pset, and whenever I check my answer using

`./fifteen 3 < ~cs50/pset3/3x3.txt`
, the program doesn't seem to be comparing my solved puzzle with my
`win[][]`
array . End result is that I have made an illegal move.

Could this be a problem that
`board[i][j]==win[i][j]`

``````         /**
* fifteen.c
*
* Computer Science 50
* Problem Set 3
*
* Implements the Game of Fifteen (generalized to d x d).
*
* Usage: ./fifteen d
*
* whereby the board's dimensions are to be d x d,
* where d must be in [MIN,MAX]
*
* Note that usleep is obsolete, but it offers more granularity than
* sleep and is simpler to use than nanosleep; `man usleep` for more.
*/

#define _XOPEN_SOURCE 500

#include <cs50.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

// board's minimal dimension
#define MIN 3

// board's maximal dimension
#define MAX 9

// board, whereby board[i][j] represents row i and column j
int board[MAX][MAX];

// board's dimension
int d;

// prototypes
void clear(void);
void greet(void);
void init(void);
void draw(void);
bool move(int tile);
bool won(void);
void save(void);

int main(int argc, string argv[])
{
// greet player
greet();

// ensure proper usage
if (argc != 2)
{
printf("Usage: ./fifteen d\n");
return 1;
}

// ensure valid dimensions
d = atoi(argv[1]);
if (d < MIN || d > MAX)
{
printf("Board must be between %i x %i and %i x %i, inclusive.\n",
MIN, MIN, MAX, MAX);
return 2;
}

// initialize the board
init();

// accept moves until game is won
while (true)
{
// clear the screen
clear();

// draw the current state of the board
draw();

// saves the current state of the board (for testing)
save();

// check for win
if (won())
{
printf("ftw!\n");
break;
}

// prompt for move
printf("Tile to move: ");
int tile = GetInt();

// move if possible, else report illegality
if (!move(tile))
{
printf("\nIllegal move.\n");
usleep(500000);
}

// sleep for animation's sake
usleep(500000);
}

// that's all folks
return 0;
}

/**
* Clears screen using ANSI escape sequences.
*/
void clear(void)
{
printf("\033[2J");
printf("\033[%d;%dH", 0, 0);
}

/**
* Greets player.
*/
void greet(void)
{
clear();
printf("GAME OF FIFTEEN\n");
usleep(2000000);
}

/**
* Initializes the game's board with tiles numbered 1 through d*d - 1,
* (i.e., fills board with values but does not actually print them),
* whereby board[i][j] represents row i and column j.
*/
void init(void)
{
// TODO

//populates the board with all the numbers and the blank space being 0
for(int i=0; i<d; i++)
{
for(int j=0;j<d;j++)
{
board[i][j]= (d*d)-(i*d)-j-1;
//Swap 2 & 1 if number of tiles are even)

if( (d*d)%2 == 0 )
{
//Assign value for original value of 2 to become 1 (swapping)
board[d-1][d-3] = 1;
//Assign value for original value of 1 to become 2 (swapping)
board[d-1][d-2] = 2;

// printf(" %d ",board[i][j]);

}
}
}
}

/**
* Prints the board in its current state.
*/
void draw(void)
{
// TODO
for(int i=0;i<d;i++)
{
for(int j=0;j<d;j++)
{
if(board[i][j]>=10)
{
printf(" %d", board[i][j]);
}

if(board[i][j]<10 && board[i][j]>0)
{
printf(" %2d", board[i][j]);
}

if(board[i][j]== 0)
{
printf("  _");
}

}

printf(" \n");
}
}

/**
* If tile borders empty space, moves tile and returns true, else
* returns false.
*/
bool move(int tile)
{

// TODO

//Find the tile player entered
for(int i=0;i<d;i++)
{
for(int j=0;j<d;j++)
{
//If tile entered is valid
if(tile==board[i][j])
{
// temp value to store tile player wants to move

//check if empty is right of tile | if valid, swap
if(board[i][j+1]==0 && (j+1<d))
{
board[i][j+1]=tile;
board[i][j]=0;
return true;
}

//check if empty is left of tile | if valid, swap
if(board[i][j-1]==0&& (j-1>=0))
{
board[i][j-1]=tile;
board[i][j]=0;
return true;
}

//check if empty is top of tile | if valid, swap
if(board[i-1][j]==0 && (i-1>=0))
{
board[i-1][j]=tile;
board[i][j]=0;
return true;
}

//check if empty is bottom of tile | if valid, swap
if(board[i+1][j]==0 && (i+1<d))
{
board[i+1][j]=tile;
board[i][j]=0;
return true;
}

else
return false;

}

}

}
return false;

}

/**
* Returns true if game is won (i.e., board is in winning configuration),
* else false.
*/
bool won(void)
{
// TODO
int win[MAX][MAX];

for(int i=0;i<d;i++)
{
for(int j=0; j<d; j++)
{
win[i][j]= (i*d)+(j+1);

if(win[i][j]==d*d)
win[i][j]=0;

if(board[i][j]== win[i][j])
return 0;
}

}
return false;
}

/**
* Saves the current state of the board to disk (for testing).
*/
void save(void)
{
// log
const string log = "log.txt";

// delete existing log, if any, before first save
static bool saved = false;
if (!saved)
{
saved = true;
}

// open log
FILE* p = fopen(log, "a");
if (p == NULL)
{
return;
}

// log board
fprintf(p, "{");
for (int i = 0; i < d; i++)
{
fprintf(p, "{");
for (int j = 0; j < d; j++)
{
fprintf(p, "%i", board[i][j]);
if (j < d - 1)
{
fprintf(p, ",");
}
}
fprintf(p, "}");
if (i < d - 1)
{
fprintf(p, ",");
}
}
fprintf(p, "}\n");

// close log
fclose(p);
}
``````

Could this be a problem that board[i][j]==win[i][j] are comparing addresses instead of the values?

No, you just got the comparison and the return value in the winning configuration wrong (1 is true, 0 is false; to not get confused, just use 1 and 0), so change in `won()`

``````                         if(board[i][j]== win[i][j])
``````

to

``````                         if (board[i][j] != win[i][j])
``````

and

``````              return false;
``````

to

``````            return 1;
``````

then it works.

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