#include <iostream>
#include <ctime>    //for time method
#include <cstdlib>  //for rand & srand

using namespace std;


 
//  #1 The program starts by displaying an introduction of the game, including its rules
    void HowToPlay()  {
        cout << "How to play the Game of Nim" << endl;
        cout << "Initially there is a pile of n stones, where n is a random integer between 10 & 21 (inclusive)" << endl;
        cout << "Each player (the computer vs. the human player) alternates turns removing 1, 2, or 3 stones." << endl;
        cout << "The player who makes the last move loses.\n" << endl;
        return;
}

int main()  {
    HowToPlay();

//  #2 It then asks the human player to choose between an easy mode and a hard mode.
        char mode;
        cout << "Would you like to play Easy mode or Hard mode? (e for easy h for hard): \n";
        cin >> mode;
        
        if (mode == 'e')   {
              cout << "You have chosen the easy mode." << endl;
        } else  {
              cout << "You have chosen the hard mode." << endl;
        }

// #3 The size of the pile of stones should be a random number between 10 and 21, inclusive  

    srand (time(0));
	int randNumStones = 10 + rand() % 11;

    cout << "\nThe initial number of stones is " << randNumStones << endl;


/*  #4 The program chooses a player randomly to start the game (i.e. the computer and the 
    human player should each have an equal chance of taking the first move).*/

    srand (time(0));
    cout << "Now a roll of the die to determine who plays first...\n" << endl;    
	int turn = 1 + rand() % 2;

    if (turn == 1)    {
        }
    else    {
        cout << "The computer plays first." << endl;
    }

/*  #5 When it is the human player’s turn, the human player should be allowed to remove 1, 2, or 3 stones
    but never more than the number of stones left.*/

//    cout << "It is your turn. How many stones would you like to remove? (1-3): ";

    int lessStones, currentStones = randNumStones;
    while (currentStones >= 1)  {
    if(turn == 1){
        while(true) {
        cout << "Your turn. How many stones would you like to remove? \n";
        cin >> lessStones;  
    if(lessStones >= 1 && lessStones <= 3 && lessStones <= currentStones)   {

        cout << "You removed " << lessStones << " from the pile" << endl;
        currentStones = currentStones - lessStones;
        cout << "The pile now has " << currentStones << " stones left.\n\n";
        break;
    } else {
        cout << "choose only 1-3 stones" << endl;  
    }   
}
        turn = 2;
    }
    else {
// #6 computer behavior
    if(mode == 'e') {
        int randNum = 1 + rand() % 3;
        if (randNum > currentStones)    {
        randNum = 1 + rand() % currentStones;            
        }
        currentStones = currentStones - randNum;
        cout << "Computer removed " << randNum << " from the pile" << endl;
        cout << "The pile now has " << currentStones << " stones left.\n\n";
    } else {
        if(currentStones %4 == 1)  {
            lessStones = 1;
        } else if(currentStones %4 == 3) {
            lessStones = 2;
        } else if (currentStones %4 == 2)   {
            lessStones = 1;
        } else {
            lessStones = 3;
        }
        currentStones = currentStones - lessStones;
        cout << "Computer removed " << lessStones << " from the pile" << endl;
        cout << "The pile now has " << currentStones << " stones left.\n\n";
    }
        turn = 1;
    }}
    if (turn == 1) {
        cout << "You won!" << endl;
    } else {
        cout << "You lose" << endl;
    }
    
}






 
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#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
}