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 the 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 the first element is ‘a’ and the second element is ‘b’. We use x as an 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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// C++ 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 = 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.
import java.io.*;
  
class GFG {
  
// Returns a if x is 0 and returns
// b if x is 1.
static int assignValue(int a, int b, int x)
    return (1 - x) * a + x * b;
}
          
// Driver code
public static void main (String[] args) 
{
    int y = assignValue(3, 7, 0);
          
    System.out.println(y);
}
}
  
// This code is contributed by ShubhamCoder

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Python3

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# Python3 program to pick a value among two
# according to the value of a third variable.
  
# Returns a if x is 0 and returns
# b if x is 1.
def assignValue(a, b, x):
      
    return (1 - x) * a + x * b
      
# Driver code
y = assignValue(3, 7, 0)
print(y)
  
# This code is contributed by ShubhamCoder

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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;
  
class GFG {
  
// Returns a if x is 0 and returns
// b if x is 1.
static int assignValue(int a, int b, int x)
    return (1 - x) * a + x * b;
}
      
// Driver code
public static void Main()
{
    int y = assignValue(3, 7, 0);
      
    Console.WriteLine(y);
}
}
  
// This code is contributed by ShubhamCoder

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Output :

3

Time Complexity: O(1)
Thanks to Forrest Smith for suggesting the 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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