# C++ Program to Generate a Random Subset by Coin Flipping

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This is a C++ program to generate a random subset by coin flipping.

Problem Description

1. This algorithm prints a subset of the given array using coin flipping method.
2. The time complexity of this algorithm is O(n).

Problem Solution

1. This algorithm takes the input of ‘n’ data element and prints a possible subset.
2. For that, it generates n bit random sequence of 0 or 1 like a coin flipping.
3. Exit.

Program/Source Code

C++ Program to generate a random subset by coin flipping.
This program is successfully run on Dev-C++ using TDM-GCC 4.9.2 MinGW compiler on a Windows system.

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

using namespace std;

int main()
{
int i, n;
cout<<"\nEnter the number of element array have: ";
cin>>n;

int arr[n];
cout<<"\n";

// Take the input of the array.
for(i = 0; i < n; i++)
{
cout<<"Enter "<<i+1<<" element: ";
cin>>arr[i];
}

// Print the subset using .
cout<<"\nThe random subset of the given set is: \n\t{ ";
for(i = 0; i < n; i++)
{
// Randomly generates 0 or 1 as coin flipping and print the array element if it is 1.
if(rand()%2 == 1)
cout<<arr[i]<<" ";
}
cout<<"}";

return 0;
}```
Program Explanation

1. Take the input of an array of ‘n’ data element.
2. Using rand()%2, generate a random binary sequence of length n.
3. While generating n bit binary sequence if the bit generated is 1 then print the corresponding array element.
4. Exit.

Runtime Test Cases
```Case 1:
Enter the number of element array have: 5

Enter 1 element: 1
Enter 2 element: 2
Enter 3 element: 3
Enter 4 element: 4
Enter 5 element: 5

The random subset of the given set is:
{ 1 2 5 }
Case 2:
Enter the number of element array have: 7

Enter 1 element: 1
Enter 2 element: 5
Enter 3 element: 8
Enter 4 element: 2
Enter 5 element: 3
Enter 6 element: 4
Enter 7 element: 9

The random subset of the given set is:
{ 1 5 3 }```

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