Programming puzzle (Assign value without any control statement)

Given four integers ‘a’, ‘b’, ‘y’ and ‘x’, where ‘x’ can only be either zero or one. Your task is as follows:

  • If ‘x’ is zero assign value ‘a’ to the variable ‘y’
  • If ‘x’ is one assign value ‘b’ to the variable ‘y’.

It is not allowed to use any conditional operator (including ternary operator).

Examples :

Input  : a = 3, b = 7,  x = 1
Output : y = 7

Input : a = 3, b = 7, x = 0
Output : y = 3

The idea is to create an array of size two where first element is ‘a’ and second element is ‘b’. We use x as index in the array.

C++

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// CPP program to pick a value among two
// according to value of a third variable.
#include <iostream>
using namespace std;
  
// Returns a if x is 0 and returns
// b if x is 1.
int assignValue(int a, int b, bool x)
{
    int arr[] = {a, b};
  
    return(arr[x]);
}
  
// Driver code
int main()
{
    int y = assignValue(3, 7, 0);
    cout << y;
    return 0;
}

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Java

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// Java program to pick a value among two
// according to value of a third variable.
class GFG {
  
    // Returns a if x is 0 and returns
    // b if x is 1.
    static int assignValue(int a, int b, int x)
    {
        int arr[] = {a, b};
  
        return (arr[x]);
    }
  
    // Driver code
    public static void main(String[] args)
    {
        int y = assignValue(3, 7, 0);
        System.out.println(y);
    }
}
  
// This code is contributed by  Smitha Dinesh Semwal.

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Python3

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# Python 3 program to
# pick a value among two
# according to value
# of a third variable.
  
# Returns a if x
# is 0 and returns
# b if x is 1.
def assignValue(a, b, x):
  
    arr = [a, b]
    return(arr[x])
  
  
# Driver code
y = assignValue(3, 7, 0)
  
print(y)
  
# This code is contributed by
# Smitha Dinesh Semwal

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C#

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// C# program to pick a value among two
// according to value of a third variable.
using System;
  
public class GFG {
   
    // Returns a if x is 0 and returns
    // b if x is 1.
    static int assignValue(int a, int b, int x)
    {
        int []arr = {a, b};
   
        return (arr[x]);
    }
   
    // Driver code
    public static void Main()
    {
        int y = assignValue(3, 7, 0);
        Console.WriteLine(y);
    }
}
// This code is contributed by PrinciRaj1992

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PHP

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<?php
// PHP program to pick a value 
// among two according to value
// of a third variable.
  
// Returns a if x is 0 and 
// returns b if x is 1.
  
function assignValue($a, $b, $x)
{
    $arr = array($a, $b);
  
    return($arr[$x]);
}
  
// Driver code
$y = assignValue(3, 7, 0);
echo $y;
  
// This code is contributed by ajit
?>

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Output :

 3

Alternate Solution :

C++

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// CPP program to pick a value among two
// according to value of a third variable.
#include <iostream>
using namespace std;
  
// Returns a if x is 0 and returns
// b if x is 1.
int assignValue(int a, int b, bool x)
{   
    return (1 - x)*a + x*b;
}
  
// Driver code
int main()
{
    int y = assValue(3, 7, 0);
    cout << y
    return 0;
}

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Output :

 7

Time Complexity: O(1)
Thanks to Forrest Smith for suggesting above solution.

This article is contributed by Maajid Bashir. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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