Thread: Latin Square Generator. Code won't keep looping.

Hi all,

The code below I've compiled with GCC using cygwin.
when running the program you can input the size (N) of the latin square to find. IE: N*N
I can generate n=2 (2 by 2) squares and n=3 (3 by 3) squares.
But nothing higher, why? Well only because the code seems to want to terminate after however many loops. I was hoping it would be obvious as to why, though I can't see why this wouldn't just keep looping forever.

Maybe someone with fresh eyes might.

Code:

#include <stdlib.h>
#include <time.h>
#include <stdio.h>

int count,size,horz,vert,checking_dups;
int skip_input=0;
int grid[100][100];

Display_Grid()
{
for(count=0; count<=40; count++)
{
printf("\n");
}

printf("---------------Displaying grid---------------\n");

for(vert=1; vert<=size; vert++)
{
	for(horz=1; horz<=size; horz++)
	{
	printf("%d", grid[horz][vert]);
	printf(" ");
	}
printf("\n");
}

printf("\n---------------------------------------------\n");
}

Gen_Numbers()
{
for(vert=1; vert<=size; vert++)
{
	for(horz=1; horz<=size; horz++)
	{
	grid[horz][vert] = (rand() % (size - 1 + 1) + 1);
	}
}
}

Check_dups_on_rows()
{
	for(vert=1; vert<=size; vert++)
	{
		for(horz=1; horz<=size; horz++)
		{
			for(checking_dups=1; checking_dups<size; checking_dups++)
			{
				if(grid[horz][vert]!=grid[horz+checking_dups][vert])
				{}
				else//duplicates found
				{
				skip_input=1; //skips grid size input goes straight to gen numbers again
				main();
				} 
			}
		}
	}
}

Check_dups_on_columns()
{
	for(horz=1; horz<=size; horz++)
	{
		for(vert=1; vert<=size; vert++)
		{
			for(checking_dups=1; checking_dups<size; checking_dups++)
			{
				if(grid[horz][vert]!=grid[horz][vert+checking_dups])
				{}
				else//duplicates found
				{
				skip_input=1; //skips grid size input goes straight to gen numbers again
				main();
				}
			}
		}
	}
}

main()
{
if(skip_input==1)
{
start:
Gen_Numbers();
Check_dups_on_rows(); //checks for duplicates in rows
Check_dups_on_columns(); //checks for duplicates in columns
Display_Grid();
goto start;
}
else
{
/*rand*/
/*x = (rand() % (max - min + 1) + min);*/
printf("enter grid size (99 max) N^x: x=:");
scanf("%d",&size);
goto start;
}

}