Implementation of N queen Problem in C.

Here is the code..

# include <stdio.h>

 # include <stdlib.h>

 # include <time.h>

 typedef struct  { int x,y;

   } position ;

 void SolveProblem(int n);

 int N=0;

 void main()

 {printf("\nENTER THE SIZE OF CHESSBOARD ( N ) FOR NxN CHESSBOARD :");

  scanf("%d",&N);

  printf("\nIn Each of the solutions the Coordinates of the N-Queens are given (Row,Col) .");

  printf("\nNote that the Rows and Colums are numbered between 1 - N :\n");

  SolveProblem(N);

  getchar();

 }

 void SolveProblem(int n)

 {

 int counter1,counter2=-1,counter3=-1;

 static int counter=0,choice;

 int d[100][3]={0};

 int *stack2;

 position Position1,Position2,Position3;

 position *head1=(position *)malloc(n*n*sizeof(position));

  stack2=(int *)malloc(n*sizeof(int));

 for(counter1=n-1;counter1>=0;counter1--)

{ Position1.x=0;

 Position1.y=counter1;

 head1[++counter2]=Position1;

};

  while(counter2>=0){ Position1=head1[counter2--];

 while(counter3>=0 && Position1.x<=counter3){

 Position2.x=counter3;

 Position2.y=stack2[counter3--];

 d[Position2.y][0]=0;

 d[Position2.x+Position2.y][1]=0;

 d[Position2.x-Position2.y+n][2]=0;};

 stack2[++counter3]=Position1.y;

 d[Position1.y][0]=1;

 d[Position1.x+Position1.y][1]=1;

 d[Position1.x-Position1.y+n][2]=1;

if(counter3==n-1)

 {

  counter++;

  printf("\nSOLUTION # %d:",counter);

  for(counter1=0;counter1<=counter3;counter1++)

   printf("(%d,%d) " ,counter1+1, stack2[counter1]+1);

  if(counter%10==0){printf("\nEnter 1 to Continue , 0 to end.");

    scanf("%d",&choice);

    if(choice==0)

    exit(0);

    };

Position2.x=counter3;

  Position2.y=stack2[counter3--];

  d[Position2.y][0]=0;

  d[Position2.x+Position2.y][1]=0;

  d[Position2.x-Position2.y+n][2]=0;}

  else{for(counter1=n-1;counter1>=0;counter1--)

      if(d[counter1][0]==0 && d[Position1.x+1+counter1][1]==0 && d[n+Position1.x+1-counter1][2]==0)

{Position3.x=Position1.x+1;

Position3.y=counter1;

head1[++counter2]=Position3;

};

  }

}

  }