Nested loops with C++ coin toss

Question

I have to write a program that runs a loop for a coin toss. I am supported to enter a number into the console and have it run a loop of the coin toss for that many times. I need to use nested loops. I have been working on this for hours and cannot make it work.

The console i/o is supposed to look like below:
Enter the number of tosses to perform [0=exit]: 3 Heads Tails Heads

Enter the number of tosses to perform [0=exit]: 2 Tails Tails

Enter the number of tosses to perform [0=exit]: 0

This is the code i have so far:

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

int main ()
{
  srand(time(0));rand(); 
  int result = rand() % 2;
  while (true)
  {
    int n; // this many tosses
    cout << "How many tosses";
    cin >> n;
    cin.ignore (1000, 10);
    if (n == 0)
      break;

    for (int i = 0; i < n; i++)
    //random number generator
    {    
      if (result == 0)
        cout<< "Heads"<<endl;
      else if (result == 1)
        cout << "Tails"<<endl;
      else if (result != 0 || result !=1) 
        return 0;
    } //for 
  }//while
}//main

score 2 · Answer 1 · answered Dec 03 '11 at 01:17

Your for loop doesn't have the part that you are actually trying to execute inside of {}. Try adding the braces around the part you want to loop and see if that fixes it for you.

I edited the indentation in your code to show you the only line that will actually be looping (the srand(time(0)))

score 1 · Answer 2 · edited May 22 '13 at 01:58

1

You need brackets around the loop block, i.e.

for( int i = 0; i < n; i++ )
{
    // Code goes here
}

As shown above, you need to initialize i.
Put the seeding of rand() before the while(...) loop.

edited May 22 '13 at 01:58

Drew Chapin

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answered Dec 03 '11 at 01:21

Fredrik Ullner

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Alright that partially worked, but its still not randomizing the heads and tails. – David Dec 03 '11 at 01:33
1

Seeding is the srand part, you need of course the actual randomization ("int result = rand % 2") in the loop... – Fredrik Ullner Dec 03 '11 at 01:38
Also, FYI, your last else-if will never execute, so it's meaningless. (Furthermore, the "else if(result==1)" can then simply be an else...) – Fredrik Ullner Dec 03 '11 at 01:40

score 0 · Answer 3 · answered Dec 03 '11 at 01:41

You need to move int result = rand() % 2; inside your for loop! Otherwise you will get the same result every single time until you restart the application.

for (int i = 0; i < n; i++)
        //random number generator
{    
    int result = rand() % 2;
    if (result == 0)
         cout<< "Heads"<<endl; /* to make your output look like your example you should removed the <<endl from here */
    else if (result == 1)
        cout << "Tails"<<endl; /* and here */
    else if (result != 0 || result !=1) 

        return 0;
} //for 

/* and put it here */
cout << endl;

Nested loops with C++ coin toss

3 Answers3