C Tetris, Place Block

Question

So I am working on a Tetris game as a school project in C. I got a little problem with the following situation. In Tetris when one completes a horizontal row, the row should be deleted and everything above the row should move down one place.The weird thing about my code is that when I place a block on the left or center of the board,the block stays there like it should. But when I place a block on the right side of the board, it is immediately deleted. I put my source code below so you can see what I am talking about.

Function checkfory (int ycheckup,int yp)

        if(ycheckup==1)
        {
            yp++;
            return yp;
        }
        else if(ycheckup==0)
        {
            yp=0;
            return yp;
        }

Main:

int Block_O[2][2] = {{1,1},{1,1}};

int printb[8][4] = {{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}};
int saveb[8][4] =  {{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}};


int x;
int y;

int i;

int xp = 0;
int yp = 0;
int ycheckup = 0;
int ch1;
int ch2;
int ytemp;

int ycheck = 0;
int xcheck = 2;
while(1)
{

    for(y=0;y<8;y++)
    {
        for(x=0;x<4;x++)
        {
            if(y==ycheck && x==xcheck || y==ycheck+1 && x==xcheck || y==ycheck && x==xcheck+1 || y==ycheck+1 && x==xcheck+1)//Looks for place to put block in
                {
                    //printf(" %d ",xp);
                    printb[y][x] = Block_O[yp][xp];
                    printf("%d", printb[y][x]);
                    ycheckup=1;
                    xp++;
                }
            else
                {
                    printb[y][x] = saveb[y][x];
                    printf("%d", printb[y][x]);
                    ycheckup=0;
                }

        }
        //checkycor(ycheck,printb);
        yp = checkfory(ycheckup, yp);
        xp=0;

        printf("\n");

    }

    for(i=0; i<30000000; i++) //Delay
    {
        ;
    }
    ycheck++;
    system("cls");

    if(ycheck==7 || printb[ycheck+1][xcheck] == 1 || printb[ycheck+1][xcheck+1] == 1 ) //Checks for correlation
    {
        for(y=0;y<8;y++)
        {
            for(x=0;x<4;x++)
            {
                saveb[y][x] = printb[y][x];
                        if((printb[y][x] == 1) && (printb[y][x+1] == 1) && (printb[y][x+2] == 1) && (printb[y][x+3] == 1)) //Checks for full row
                        {
                            ytemp = y;
                            for(y=ytemp;y>0;y--)
                            {
                                for(x=0;x<4;x++)
                                {
                                    if(y>0)
                                    {
                                        saveb[y][x] = printb[y-1][x]; //moves everything above deleted row, one row down

                                    }
                                    else
                                    {
                                        saveb[y][x] = 0;
                                    }
                                    printb[y][x] = saveb[y][x];
                                }

                            }

                        }


            }
        }

        ycheck=0;
    }

    if (kbhit()!=0)
        {
            ch1 = getch();
            ch2 = 0;
            ch2 = getch();

            switch(ch2)
            {
            case 75:
                    xcheck--;
                break; //left
            case 77:
                    xcheck++;
                break;
            default:
                ;
                break;
            };
        }

}

Answer 1

I'm not sure why you shared checkfory(), that doesn't seem to be related to the logic of clearing a row. A couple comments wouldn't hurt, so we'd easily know what part is for moving the block coming down, and what is for clearing a row once the piece is in its final position.

I do see what seems to be an error in the if statement that looks for a full row - it depends on x, but it's inside a loop incrementing x. It appears to me that check will only work correctly on the first loop, and is reading into the next line of blocks after that. So a block placed on the right side will do a compare on that block and the remaining 3 checks are against blocks on the next row.

I think you have a misplaced end-brace, and the first for-x loop in the middle section should just be the one line that makes a shadow copy of the current row (to be moved down if needed).