help with getch()

[Devra]

Hi, I'm working on a c++ program. It's a sudoku solver and till now I got it.

#include<stdio.h>
int sudoku[9][9];//The array which stores entries for the sudoku
void solvesudoku(int,int);
int checkrow(int row,int num)
{//This function checks whether we can put the number(num) in the row(row) of the Sudoku or not
int column;
for(column=0;column<9;column++)
if(sudoku[row][column]==num)
return 0 ;//If the number is found already present at certain location we return zero
return 1;//If the number is not found anywhere we return 1
}
int checkcolumn(int column,int num)
{//This function checks whether we can put the number(num) in the column(column) of the Sudoku or not
int row;
for(row=0;row<9;row++)
if(sudoku[row][column]==num)
return 0;//If the number is found already present at certain location we return zero
return 1;//If the number is not found anywhere we return 1
}
int checkgrid(int row,int column,int num)
{//This function checks whether we can put the number(num) in the 3*3 grid or not
//We get the starting row and column for the 3*3 grid
row=(row/3)*3 ;
column=(column/3)*3;
int r,c;
for(r=0;r<3;r++)
for(c=0;c<3;c++)
if(sudoku[row+r][column+c]==num)
return 0;//If the number is found already present at certain location we return zero
return 1;//If the number is not found anywhere we return 1
}
void navigate(int row,int column)
{//Function to move to the next cell in case we have filled one cell
if(column<8)
solvesudoku(row,column+1);
else
solvesudoku(row+1,0);
}
void display()
{//The function to display the solved Sudoku
int row,column;
printf("THE SOLVED SUDOKU \n");
for(row=0;row<9;row++)
{
for(column=0;column<9;column++)
printf("%d ",sudoku[row][column]);
printf("\n");
}
getch();
}
void solvesudoku(int row,int column)
{
if(row>8)//If the row number is greater than 8 than we have filled all cells hence we have solved the sudoku
display();
if(sudoku[row][column]!=0)
navigate(row,column);//If the value filled at a cell is not zero than it is filled with some value from 0 to 9 hence we move further
else
{
int ctr;//This is a counter to check numbers from 1 to 9 whether the number can be filled in the cell or not
for(ctr=1;ctr<=9;ctr++)
{//We check row,column and the grid
if((checkrow(row,ctr)==1)&&(checkcolumn(column,ctr)==1)&&(checkgrid(row,column,ctr)==1))
{
sudoku[row][column]=ctr;
navigate(row,column);
}
}
sudoku[row][column]=0;//No valid number was found so we clean up and return to the caller.
}

}
int main()
{
int row,column;
printf("Enter the desired sudoku and enter 0 for unknown entries\n");
for(row=0;row<9;row++)
for(column=0;column<9;column++)
scanf("%d",&sudoku[row][column]);
solvesudoku(0,0);//We start solving the sudoku.
}

I got this on a web site since I need it in my Computer class. But it has a problem with getch(); The message says "Identifier "getch" undefined".
Please help. Thanks. Devra

[MiiNiPaa]

Just delete it. If you gon sane IDE it will stop and let you read output anyway.

[Chervil]

getch() is non-standard. If you want to use it, add this line at the top of the program:

#include <conio.h>

However, not all compilers support this.

[Devra]

Thanks very much now I can run the program but after writing info it show the output and it closes within a second.

[Yanson]

You can put cin.ignore(); at the end of the program to hold it open.

[Chervil]

Which change did you make, delete the getch or add the include?

[Devra]

Delete the getch.

[Yanson]

Yanson wrote:

You can put cin.ignore(); at the end of the program to hold it open.

whoops you can ignore this I just noticed that this is c not c++. For some reason I can't edit my post

[Devra]

The program is c?

[MiiNiPaa]

add

std::cin.ignore(500,'\n');//Or include <limits> and place std::numeric_limits<std::streamsize>::max() instead of 500
std::cin.get();

instead of getch

The program is c?

It doesn't use any of C++ features preferring old non-safe C methods instead.

[Chervil]

Use either getch() if supported in conio.h, otherwise use the standard getchar() which is in stdio.h

getchar() requires some character followed by enter, getch() requires just a single keystroke.

[Devra]

Can I transform the old non-safe c method to C++?

[MiiNiPaa]

Well... Stream operations instead of printf()/scanf(), return bool instead of int where needed.