RandomTrouble

I am trying figure out how to generate random choices by the computer. I think I know what I'm doing in theory but I need someone to point me in the right direction as far as coding. I know the random number generator works, so I want to set it up so that if the random number is 0 then computerChoice is going to be equal to word "Paper", if the number is 1, then computerChoice is equal to "Rock"..and so on and so forth. I didn't think it would work to just set the variable equal to the word, I gave it a try and sure enough it didn't work. Could someone tell me how I can make computerChoice equal to a certain word?

Code:

#include <stdlib.h>
#include <time.h>
#include <iostream.h>

int main()
{

char computerChoice[10]=""
 srand((unsigned)time(NULL)); //Casts time's return to unsigned
  int d=rand()%3;  //Should be more random now  

if(d==0)
{
cout<<"Computer choice: Paper"<<endl;
computerChoice="Paper";
}
if(d==1)cout<<"Computer choice: Rock"<<endl;

if(d==2)cout<<"Computer choice: Scissors"<<endl;

  cout<<d;
  return 0;
}

Instead of using char arrays, you could use the string class.

Code:

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

int main()
{

   string computerChoice;
   srand((unsigned)time(NULL)); //Casts time's return to unsigned
   int d=rand()%3;  //Should be more random now  

   if (d==0)
   {
      cout<<"Computer choice: Paper"<<endl;
      computerChoice="Paper";
   }
   else if (d==1)
   {
      cout<<"Computer choice: Rock"<<endl;
      computerChoice="Rock";
   }

   else if (d==2)
   {
      cout<<"Computer choice: Scissors"<<endl;
      computerChoice="Scissors";
   }
   cout<<d;
   return 0;
}

Hmm...that works for this portion of the game, but further in the game I use strcmp, i get a error message that says "function call 'strcmp({1val} char[15],{1val} std:basic_string"....ect. Im guessing you can't compare a char array to a string array. Do i have to define all the variables as strings?..or is there a different statement to compare these things?


(just snippet of the code)

Code:

	if((strcmp(playerChoice,computerChoice))==0)
	{
	cout<<"Tie"<<endl;

	}

	if ((strcmp(playerChoice,computerChoice))==2)
	{
	cout<< " paper beats rock, computer wins this round"<<endl;
	}

	if((strcmp(playerChoice,computerChoice))==3)
	{
	cout<<"scissors over paper,player wins this round "<<endl;
	}

>or is there a different statement to compare these things?
Well, you could do this:

Code:

    if((strcmp(playerChoice,computerChoice.c_str()))==0) // Strings match

ok, I tested the if statements that contain the string comparisons in order to determine whether the computer or player wins and it worked fine, yet when I put it in the program everything works up to that part, the player chooses a choice and then it shows the computer choice but it never prints the statement that says who won that round. I haven't gotten any error message..is there something wrong in my coding?

Code:

#include<iostream>
#include<math.h>
#include<string>
#include<stdlib.h>
#include<cstdlib>
#include<ctime>

int checkLoop;
char yesOrno[10]="";		

using namespace std;

int main()
{


while(checkLoop == 0){   				
	
		//intro screen
		cout << "                                                                             " << endl;
		cout << "            Rock          Paper         Scissors                             " << endl;
		cout << " ____________________________________________________________________________" << endl;
		cout << "| This is a game of rock, paper, scissors. You will the best of three rounds |" << endl;
		cout << "|  against the computer. To pick either rock, paper, or scissors simply      | " << endl;
		cout << "|  type in your choice and hit enter. The computer will randomly pick its    | " << endl;
		cout << "|  choice. At the end of the game type y to play again & n to end the game.  | " << endl;
		cout << "|               Do you understand?  please enter y or n                      | " << endl;
		cout << "|____________________________________________________________________________| " << endl; 
		
		//user input
		cin.getline(yesOrno, 10);
	
if((strcmp(yesOrno,"n")==0)||(strcmp(yesOrno,"y")==0))			//if the user input is a y or n go into this other loop
	{	
		if(strcmp(yesOrno,"y")==0)
			{
				checkLoop=1;									
				system("CLS");						
				cout<< "Get ready to start the game"<<endl;
				}
			else												//if the user input is no repeat the directions
			
			{
				system("CLS");
				cout<< "Read the directions again";
				checkLoop=0;									//makes this loop repeat until y or n entered
			}	
				}	 
else
	{ 
	 				
	 	cout<< " Enter a y or n "<<endl;						//if the user enters something other than a y or n print this statement										
	 	cout<<endl;
	 	cout<<endl;	
	 	}

	}



 
string computerChoice;

char playerChoice[20]="";

cout << "Input player choice."<<endl;
cin.getline(playerChoice,10);




if((strcmp(playerChoice,"paper")==0)||(strcmp(playerChoice,"rock")==0)||(strcmp(playerChoice,"scissors")==0))

{

   srand((unsigned)time(NULL)); 
   int d=rand()%3;  
   
   if (d==0)
   {
      cout<<"Computer choice: Paper"<<endl;
      computerChoice=="Paper";
   }
    if (d==1)
   {
      cout<<"Computer choice: Rock"<<endl;
      computerChoice=="Rock";
   }

   if (d==2)
   {
      cout<<"Computer choice: Scissors"<<endl;
      computerChoice=="Scissors";
   }
   cout<<d;
  
//this is the part that doesn't show up 

	if((strcmp(playerChoice,computerChoice.c_str()))==0)cout<<"Tie"<<endl;
	
	if ((strcmp(playerChoice,computerChoice.c_str()))==2)cout<< " paper beats rock, computer wins this round"<<endl;
	
	if((strcmp(playerChoice,computerChoice.c_str()))==3)cout<<"scissors over paper,player wins this round "<<endl;
		
	if((strcmp(playerChoice,computerChoice.c_str()))==-2)cout<<"paper beats rock,player wins this round"<<endl;
	
	if((strcmp(playerChoice,computerChoice.c_str()))==-3)cout<<"scissors beats paper, computer wins"<<endl;
	
	if ((strcmp(playerChoice,computerChoice.c_str()))==1)cout<<"rock beats scissors, computer wins this round"<<endl;
	
	if ((strcmp(playerChoice,computerChoice.c_str()))==-1)cout<<"rock beats scissors, player wins this round"<<endl;
	
}	

else

{
	cout<<"you made a mistake in typing"<<endl;
}

 
return 0;

}

>is there something wrong in my coding?

First, = and == are different operators:
= is assignment
== is checking for equality

So:
> computerChoice=="Paper";
> computerChoice=="Rock";
> computerChoice=="Scissors";

These lines does basically does nothing. They check for equality, but don't use the result. I think you want assignment here.

Second, "Rock" and "rock" are not equal. So you must make sure everything is either uppercase or lowercase, or convert the player's choice to one case, then match the computer choice with that case.

With these changes, I think it will work.

Code:

  if((strcmp(playerChoice,computerChoice.c_str()))==  0) // Strings match

Before we run too far with this, let's consider:

Code:

if(computerChoice == playerChoice)

Just had to stick in my 2 cents.

Originally Posted by Hunter2

Code:

  if((strcmp(playerChoice,computerChoice.c_str()))==  0) // Strings match

Before we run too far with this, let's consider:

Code:

if(computerChoice == playerChoice)

Just had to stick in my 2 cents.

How about that! I have just learned a new trick, thanks Hunter.