Thread: A problem with output of a two-dimensional table

Code:

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
	int rows , cols;
	int a[rows][cols];
	int i , j;
	while(scanf("%d%d" , &rows , &cols) == 1)
	{
		for(i = 0 ; i < rows ; i++)
			for(j = 0 ; j < cols ; j++)
				a[i][j] = 2;
		for(i = 0 ; i < rows ; i++)
			for(j = 0 ; j < cols ; j++)
				printf("%d " , a[i][j]);
	}
 
	return 0;
}

The above codes are expected to show a two-dimensional table with every element being '2' . I used llcwin which claims to support C99 to run. THe codes can be compiled successfully but execution comes to a failure. I don't know why. Please give me help. Thanks.