Wondering where the error is D:

Hey guys, I'm coding a function for a game somewhat like minesweeper and I have encountered a problem. How this function is suppose to work is the user gives it a movement command and if it is a valid move, the command is executed. I have a test driver to see if the coordinates are actually correct, problem is the coordinates are displayed twice when I hit a valid command. I cant seem to find why this is happening. Any help will be much appreciated#include "util.h"

Code:

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/* file: driver */
#include "mine.h"
#include<stdio.h>

main()
{
        char command;
        int row = 0;
        int col = 0;

        printf("enter command(press q to quit):");
        command = getchar();

        while(command != 'q')
        {
                if(coordinate(command, &row, &col))
                        printf("new coordinates:[%d][%d]\n",row,col);
                else
                        printf("invalid move\n");
                command = getchar();
        }
}

/*file: util.c */
#include "tfdef.h"
#include "mine.h"
#include<stdio.h>
int coordinate(char command, int *row, int *col)
{
        switch(command)
        {
                case 'y':
                case 'Y':
                *row = *row - 1;
                *col = *col - 1;
                break;
                case 'u':
                case 'U':
                *row = *row - 1;
                break;
                case 'i':
                case 'I':
                *row = *row - 1;
                *col = *col + 1;
                break;
                case'h':
                case'H':
                *col = *col - 1;
                break;
                case 'k':
                case 'K':
                *col = *col + 1;
                break;
                case 'n':
                case 'N':
                *row = *row + 1;
                *col = *col - 1;
                break;
                case 'm':
                case 'M':
                *row = *row + 1;
                break;
                case ',':
                case '<':
                *row = *row+1;
                *col = *col+1;
                break;
        }

        if(*row < START||*col < START||*row >= MAXR)
                return FALSE;
        else
                return TRUE;

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It looks like your code is processing both the key press, as well as '\n'.

It might be because you are feeding it the command and a carriage return character when pressing enter.

Try using scanf("%c",&command);

but if that is the case, shouldn't it print the new coordinate and then invalid command?

Quote:

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Originally Posted by Thanksbro

but if that is the case, shouldn't it print the new coordinate and then invalid command?

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Where's the code that handle's "invalid command"?

In the driver I have if the function coordinate is true, print the coordinates. Otherwise print invalid command.

And what are the conditions for that function to return true or false?

The logic for that driver, is not doing what you think it is, and you don't want a valid command returned with an invalid command, every time, right?

So add a getchar() right underneath the other getchar(), and pull the newline char off the keyboard buffer, and problem solved.

if(*row < START||*col < START||*row >= MAXR)
return FALSE;
implying that you can't have a row or column less then 0 and that you can't have a row greater or equal to the maximum row.

Does that have anything to do with the command entered?

I see what you are getting at, but my if statement does solve one of my problems. However, I have just solved the problem of double printing. while(command = getchar() != '\n'); takes care of it. Thanks for everyone's help.