#include <iostream>
#include <cstdlib>
#include <unistd.h>
#include <fstream>
#include <string>
#include <sstream>

//Move OS defines up here to be used in different places
#if defined(_WIN32) || defined(WIN32) || defined(__MINGW32__) || defined(__BORLANDC__)
 #define OS_WIN
 //WINDOWS COLORS 
  #define COLOR_RED SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_RED)
  #define COLOR_WARNING SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN) 

  #define COLOR_BLUE SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_BLUE)

  #define COLOR_RESET SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 15)

#elif defined(linux) || defined(__CYGWIN__)
  #define OS_LINUX

  #define COLOR_RED "\033[31m"
  #define COLOR_GREEN "\033[32m" 
  #define COLOR_BLUE "\033[34m"
  #define COLOR_RESET "\033[0m"

#elif (defined(__APPLE__) || defined(__OSX__) || defined(__MACOS__)) && defined(__MACH__)//To ensure that we are running on a mondern version of macOS
  #define OS_MAC

  #define COLOR_RED "\033[31m"
  #define COLOR_GREEN "\033[32m" 
  #define COLOR_BLUE "\033[34m"
  #define COLOR_RESET "\033[0m"

#endif

#if defined(OS_WIN)
  #include <windows.h> // Use for windows
#endif

using namespace std;

const int gridSize = 25;
void printGrid(bool gridOne[gridSize+1][gridSize+1]);
void determineState(bool gridOne[gridSize+1][gridSize+1]);
void clearScreen(void);


int main(){

    // system( "color A" );//LGT green
    cout << COLOR_GREEN;
    clearScreen();
    bool gridOne[gridSize+1][gridSize+1] = {};
    int x,y,n;
    string nc;
    string start;
    string filename;
    cout << "                         THE GAME OF life - Implementation in C++" << endl;
    cout << endl;
    cout << endl;
    cout << endl;
    cout << "Also known simply as life, " << endl;
    cout << "is a cellular automaton devised by the British mathematician John Horton Conway in 1970." << endl;
    cout << endl;
    cout << "Rules" << endl;
    cout << "The universe of the Game of life is an infinite two-dimensional orthogonal grid of square cells," << endl;
    cout << "each of which is in one of two possible states, life or dead. Every" << endl;
    cout << "cell interacts with its eight neighbours, which are the cells that are horizontally, vertically, or diagonally adjacent." << endl;
    cout << "At each step in time, the following transitions occur:" << endl;
    cout << "1. Any live cell with fewer than two live neighbours dies, as if caused by under-population." << endl;
    cout << "2. Any live cell with two or three live neighbours lives on to the next generation." << endl;
    cout << "3. Any live cell with more than three live neighbours dies, as if by over-population." << endl;
    cout << "4. Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction." << endl;
    cout << endl;
    cout << "O - living cell" << endl;
    cout << ". - dead cell" << endl;
    cout << endl;
    cout << "Enter the number of cells, or 'r' to read cells from file: ";
    cin >> nc;
    cout << endl;

    if ( nc == "r" )
      {
	while (true)
	  {
	    
	    cout << "Enter name of file to read from: "<<endl;
	    cin  >> filename;
	    
	    ifstream readfile(filename);
	    if ( readfile.is_open() )
	      {
		string fileline,xx,yy;

		while (getline(readfile,fileline))
		  {
		    stringstream ss(fileline);
		    
		    getline(ss,xx,' ');
		    getline(ss,yy,' ');

		    x = stoi(xx);
		    y = stoi(yy);

		    gridOne[x][y] = true;
		  }
		break;
	      } else {
	      cout << "No such file, try again." << endl;
	    }
	  }
      }
    else
      {
	
	for(int i=0;i<stoi(nc);i++)
	  {
	    cout <<stoi(nc)<< "Enter the coordinates of cell " << i+1 << " : ";
	    cin >> x >> y;
	    gridOne[x][y] = true;
	    printGrid(gridOne);
	  }
      }
    cout << "Grid setup is done. Start the game ? (y/n)" << endl;
    printGrid(gridOne);
    cin >> start;
    if( start == "y" || start == "Y" )
      {
        while (true)
	  {
            printGrid(gridOne);
            determineState(gridOne);
            usleep(200000);
            clearScreen();
	  }
      }
    else
      {
        cout << COLOR_RESET;
        clearScreen();
        return 0;
      }   
}

void clearScreen(void) {
  // Tested and working on Ubuntu and Cygwin
  #if defined(OS_WIN)
    HANDLE hStdOut = GetStdHandle( STD_OUTPUT_HANDLE );
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    DWORD count;
    DWORD cellCount;
    COORD homeCoords = { 0, 0 };

    if (hStdOut == INVALID_HANDLE_VALUE) return;

    /* Get the number of cells in the current buffer */
    GetConsoleScreenBufferInfo( hStdOut, &csbi );
    cellCount = csbi.dwSize.X *csbi.dwSize.Y;

    /* Fill the entire buffer with spaces */
    FillConsoleOutputCharacter(hStdOut, (TCHAR) ' ', cellCount, homeCoords, &count);

    /* Fill the entire buffer with the current colors and attributes */
    FillConsoleOutputAttribute(hStdOut, csbi.wAttributes, cellCount, homeCoords, &count);

    SetConsoleCursorPosition( hStdOut, homeCoords );

  #elif defined(OS_LINUX) || defined(OS_MAC)
    cout << "\033[2J;" << "\033[1;1H"; // Clears screen and moves cursor to home pos on POSIX systems
  #endif

}


void printGrid(bool gridOne[gridSize+1][gridSize+1]){
    for(int a = 1; a < gridSize; a++)
        {
        for(int b = 1; b < gridSize; b++)
        {
            if(gridOne[a][b] == true)
            {
                cout << " O ";
            }
            else
            {
                cout << " . ";
            }
            if(b == gridSize-1)
            {
                cout << endl;
            }
        }
    }
}

void compareGrid (bool gridOne[gridSize+1][gridSize+1], bool gridTwo[gridSize+1][gridSize+1]){
    for(int a =0; a < gridSize; a++)
    {
        for(int b = 0; b < gridSize; b++)
        {
                gridTwo[a][b] = gridOne[a][b];
        }
    }
}

void determineState(bool gridOne[gridSize+1][gridSize+1]){
    bool gridTwo[gridSize+1][gridSize+1] = {};
    compareGrid(gridOne, gridTwo);

    for(int a = 1; a < gridSize; a++)
    {
        for(int b = 1; b < gridSize; b++)
        {
            int alive = 0;
            for(int c = -1; c < 2; c++)
            {
                for(int d = -1; d < 2; d++)
                {
                    if(!(c == 0 && d == 0))
                    {
                        if(gridTwo[a+c][b+d])
				{
					++alive;
				}
                    }
                }
            }
            if(alive < 2)
            {
                gridOne[a][b] = false;
            }
            else if(alive == 3)
            {
                gridOne[a][b] = true;
            }
            else if(alive > 3)
            {
                gridOne[a][b] = false;
            }
        }
    }
} 

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
} 

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
} 

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}  

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition); 

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}