#include <iostream>

#include <OpenGL/OpenGL.h>

#include <GLUT/glut.h>

#include <OpenGl/glu.h>

usingnamespacestd;

charchessboard[100][100]={};

intqueens;

floatW; floatH;

intsavingposition[100][2]={ };

void init(void)

{

 glClearColor(0.0,0.0,0.0,0.0);

 //glEnable(GL_DEPTH_TEST);

}

bool checking (int row, int column){

for(int i = 0; i< queens; i++){

 for(int j = 0; j < queens; j++) {

 if((j+i== column + row|| column - row == j-i || i== row || j == column) && chessboard[i][j]=='Q')

 returnfalse;

 }}

 returntrue;

}

void removeflag(int row)

{

for(int i=0; i < queens; i++)

{

 chessboard[row][i] = '0';

  

}

}

void backtracking (void)

{

for(int row = 0; row < queens; row++)

{

 for(int column = 0; column <queens; column++){

 if( checking (row,column) && chessboard[row][column] != '-'){

 chessboard[row][column] = 'Q'; removeflag(row+1);

 savingposition[row][0] = row;

 savingposition[row][1] = column;

 row++; column = -1;

 if ( row == queens ) break;

 }

 else if (column == queens-1 && chessboard[row][column] != 'Q')

 {

 row--;

 column = savingposition[row][1];

 //cout << row << " " << column << endl;

 chessboard[row][column] = '-';

 column = 0; 

 }

 }

}

}

void displaytable(void)

{

for(int i = 0; i< queens; i++){

 for(int j = 0; j < queens; j++) {

 if (chessboard[i][j] != 'Q')

 cout << '.'; 

 else

 cout << chessboard[i][j];

 }

 cout << endl;

}

}

void displayboard()

{

 glTranslatef(25, H-25, 0.0);

 glPushMatrix();

for(int i = 0; i<queens; i++){

 glPushMatrix();

 for(int j = 0; j < queens; j++) {

 if ((i+j)%2 == 0) glColor3f(1.0, 1.0, 1.0); else glColor3f(0.0, 0.0, 0.0);

 glPushMatrix(); glScalef(50.0, 50.0, 0.0);

 glutSolidCube(1);

 if(chessboard[i][j] == 'Q'){ glPushMatrix();

 glColor3f(1, 0, 0);

 glutSolidSphere(0.4, 50, 50);glPopMatrix();}

 glPopMatrix();

 glTranslatef(50.0, 0.0, 0.0);

 }

 glPopMatrix();

 glTranslatef(0.0, -50.0, 0.0);

}

 glPopMatrix();

}

void display()

{

 glClear(GL_COLOR_BUFFER_BIT);

 glPushMatrix();

 displayboard();

 glPopMatrix();

 displaytable();

 glutSwapBuffers();

}

void reshape(int w, int h)

{glViewport(0,0, (GLsizei)w, (GLsizei)h);

 glMatrixMode (GL_PROJECTION);

 glLoadIdentity();

gluOrtho2D(0, W, 0, H);

 glMatrixMode(GL_MODELVIEW);

 glLoadIdentity();//important: last line must be glLoadIdentity() for coloring with openGL

 //glTranslatef (.0, .0, -5.); //do not translate at all if glLoadIdentity() is used

}

void mouse (int button, int state, int x, int y) //mouse function...

{

int row, column;

switch(button) {

 caseGLUT_LEFT_BUTTON:

 if(state == GLUT_DOWN)

 {   row = (y/50);

 column = (x/50);

 if (checking(row, column))

 chessboard[row][column] = 'Q';}

 cout << "X -->" << x<< "Y-->" << y << endl;

 glutPostRedisplay();

 break;

 caseGLUT_RIGHT_BUTTON:

 if(state == GLUT_DOWN)

 {   row = (y/50);

 column = (x/50);

 chessboard[row][column] = ' ';}

 cout << "X -->" << x<< "Y-->" << y << endl;

 //displaytable();

 glutPostRedisplay();

 break;}

}

int main(int argc, char **argv)

{ 

int input;

 cout << "WELCOME TO N-QUEEN PROGRAM!!!"<<endl;

 cout << "1. Show The Solution by Computer!!"<<endl;

 cout << "2. Try to solve the puzzle"<<endl;

cout << "3. Exit!!!"<<endl;

 cout << "Select the NUMBER from 1-3::";

cin >> input;

switch (input)

{

 case 1:

 cout << "Please enter the number of the queens 1 to 100:"<<endl;

 cin >> queens;

 backtracking();break;

 case 2:

 cout << "What size of N queens do you want to play ?:"<< endl;

 cin >> queens;

 cout << "Left Cick on the box to select!!\n Right click to deselect ";

 break;

 case 3:

 cout << "THANK YOU FOR PLAYING"; break;

 default:

 cout << "WRONG INPUT";

 break;

}

 W = 50*queens;

 H = 50*queens;

glutInit(&argc, argv);

 glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);

 glutInitWindowSize (W, H);

 glutInitWindowPosition(0,0);

 glutCreateWindow("Chessboard");

init(); 

 glutDisplayFunc(display);

 glutMouseFunc(mouse);

 glutReshapeFunc(reshape);

 glutMainLoop();

 return0;

}