need help using a while loop

[gustavson]

Hi all,

My problem is this: I'm doing a small game in C and the problem is that in my only while loop that I'm using, I call a function. Now when I enter a letter, as required by my code, the while loop executes twice and if I type just [Enter] than it executes only once. I have no idea what I'm doing wrong and I ask if anyone could help me solving this issue. Thank you and much appreaciate your help. Here is my code:

/*
Purpose: a C game used to implement a puzzle using an array
*/

#include <stdio.h>
#include <conio.h>
#include <ctype.h>

//declare global variables used in program
int table[4][4] = {{1,4,15,7},{8,10,2,11},{14,3,6,13},{12,9,5,0}};
int count = 0;

//provide the prototype of each function
void displayTable(void);
void moveNumbers(void);
void moveRight(void);
void moveLeft(void);
void moveUp(void);
void moveDown(void);
int checkForFinish(void);
int keepCounting(int);

//start the main function
main(void){
    displayTable();
    int finished = 0;
    while(finished != 1){
        moveNumbers();
        finished = checkForFinish();
    } 
    printf("Congratulations! You finished the game!");
    printf("\n\nPress any key to exit... ");
    getche();
}

//function used to move the numbers in the grid
void moveNumbers(){
     int key;
     printf("\n\nEnter a letter(L,R,U or D): ");
     key = getchar();
     key = tolower(key);
     if(key == 'l')
          moveLeft();
     if(key == 'r')
          moveRight();   
     if(key == 'u')
          moveUp();
     if(key == 'd')
          moveDown(); 
     displayTable();
     keepCounting(key);  
}

//moves the number to the right
void moveRight(){
    int temp,i,j;
    for(i = 0; i < 4; i++){
        for(j = 0; j < 4; j++){
            if(table[i][j] == 0 && j != 0){
                temp = table[i][j-1];
                table[i][j-1] = 0;
                table[i][j] = temp;
            }
        }
    }
} 

//moves the number to the left
void moveLeft(){
    int temp,i,j;
    for(i = 3; i >= 0; i--){
        for(j = 3; j >= 0; j--){
            if(table[i][j] == 0 && j != 3){
                temp = table[i][j+1];
                table[i][j+1] = 0;
                table[i][j] = temp;
            }
        }
    }
} 

//moves the number up
void moveUp(){
    int temp,i,j;
    for(i = 3; i >= 0; i--){
        for(j = 3; j >= 0; j--){
            if(table[i][j] == 0 && i != 3){
                temp = table[i+1][j];
                table[i+1][j] = 0;
                table[i][j] = temp;
            }
        }
    }
}   

//moves the number down
void moveDown(){
    int temp,i,j;
    for(i = 0; i < 4; i++){
        for(j = 0; j < 4; j++){
            if(table[i][j] == 0 && i != 0){
                temp = table[i-1][j];
                table[i-1][j] = 0;
                table[i][j] = temp;
            }
        }
    }
}   

//function used to display the table 
void displayTable(){
    int i,j;
    for(i = 0; i < 4; i++){
        printf("\n\n");
        for(j = 0; j < 4; j++){
            if(table[i][j] == 0)
                printf("      ");
            else if(table[i][j] < 10)
                printf(" %d    ",table[i][j]);  
            else
                printf("%d    ",table[i][j]);
        }
    }
    printf("\n");   
}
    
//function used to check if the grid is arranged from 1 to 15
int checkForFinish(void){
    int i,j,temp,result;
    result = 0;
    temp = 1;
    for(i = 0; i < 4; i++){
        for(j = 0; j < 4; j++){
            if(table[i][j] == temp){
                temp += 1;
            }
        }
    }
    if(temp == 15)
        result = 1;
    return result;
}

//function used to keep count of user moves
int keepCounting(int userOption){
    if (userOption != 0){
        count += 1;
    }
    printf("\n\nTotal number of moves taken so far is: %d", count);
}

[Dave_Sinkula]

Now when I enter a letter, as required by my code, the while loop executes twice and if I type just [Enter] than it executes only once. I have no idea what I'm doing wrong and I ask if anyone could help me solving this issue. Thank you and much appreaciate your help.

You enter a letter and [Enter] -- two characters -- and the loop executes twice.
You merely hit [Enter] -- one character -- and it executes once.

If you want to read and discard the newline character that is placed in the input buffer when you press [Enter], do so.

getchar(); /* read and discard newline character */

See also.