Thread: Selecting and connect a number.

I am building a c program to select and move a number in an array.My aim is to connect 2 pairs of same number in the array. But I am not sure why the selected number be can't moved. Need help, thanks in advance.

Code:

Code:

void playgame(char box[ROW][COL])
{
  int x, y, choice2,num,direction=0;
  char input;

  do{

     printf("Please select a number (1-7) : ");
     scanf("%i",&num);

     if(num==0||num >7)
     {

     printf("Invalid!\n");


     }
     else
     {

     printf("\nNumer %i is currently selected!\n", num);

     }
    }while(num==0||num >7);

    printf("\n[1]Move\n[2]Sign out\n");
    printf("\nEnter choice: \n");
    scanf("%d",&choice2);


    switch(choice2)
    {
      case1: 
                {
                    printf("Press 'e' to go up\n");
                    
                }

                {
                    printf("Press 'd' to go right\n");

                }

                {
                    printf("Press 's' to go left\n");

                }

                {
                    printf("Press 'x' to go down\n");

                }

                    fflush(stdin);

                    scanf("%c",&input);
                break;

        case2: printf("Bye!\n");
    }



  for(x=0; x<9; x++)

  for(y=0; y<9; y++)
  {     
    if(input =='e')
  if(box[x][y]==num)
  {
   box[--x][y] =num;
   }

 if(input =='d')
  if(box[x][y]==num)
  {
   box[x][++y] = num;
   }


 if(input =='s')
    if(box[x][y] == num)
    {
        box[x][--y] = num;
    }

if(input =='x')
  if(box[x][y]==num)
  {
   box[++x][y] = num;
   }
     }


}

Code formatted and indented; please pay attention to make sure your post is readable.

Code:

void playgame(char box[ROW][COL])
{
  int x, y, choice2, num, direction = 0;
  char input;

  do {
    printf("Please select a number (1-7) : ");
    scanf("%i", &num);

    if (num == 0 || num > 7) {
      printf("Invalid!\n");
    } else {
      printf("\nNumer %i is currently selected!\n", num);
    }
  } while (num == 0 || num > 7);

  printf("\n[1]Move\n[2]Sign out\n");
  printf("\nEnter choice: \n");
  scanf("%d", &choice2);

  switch (choice2) {
  case 1:
    {
      printf("Press 'e' to go up\n");
    }
    {
      printf("Press 'd' to go right\n");
    }
    {
      printf("Press 's' to go left\n");
    }
    {
      printf("Press 'x' to go down\n");
    }

    fflush(stdin);
    scanf("%c", &input);
    break;

  case 2:
    printf("Bye!\n");
  }

  for (x = 0; x < 9; x++)
    for (y = 0; y < 9; y++) {
      if (input == 'e')
        if (box[x][y] == num) {
          box[--x][y] = num;
        }
      if (input == 'd')
        if (box[x][y] == num) {
          box[x][++y] = num;
        }
      if (input == 's')
        if (box[x][y] == num) {
          box[x][--y] = num;
        }
      if (input == 'x')
        if (box[x][y] == num) {
          box[++x][y] = num;
        }
    }
}

> box[--x][y] = num;
Presumably, you want to actually break out of these loops having moved the number once?
Doing --x is a sure way of messing up your loop control as well; consider using x-1 instead of --x

Also, you're not moving the number, since you don't actually clear box[x][y] at the same time.

> fflush(stdin);
> scanf("%c", &input);
Flushing input streams is undefined behaviour.
FAQ > Why fflush(stdin) is wrong - Cprogramming.com
If you want the next non-space character, then use
scanf(" %c", &input); // note the initial leading space in the scan format.

> for (x = 0; x < 9; x++)
You should replace literal 9 with the symbolic constants ROW and COL respectively.