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.

Implementation:

C++

// 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;
}

// C program to pick a value among two
// according to value of a third variable.
#include <stdio.h>
#include <stdbool.h>

// 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);
    printf("%d",y);
    return 0;
}

// This code is contributed by kothvvsaakash.

Java

// 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.

Python3

# 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

// 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

PHP

<?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
?>

JavaScript

<script>
// javascript 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) {
        var arr = [ a, b ];

        return (arr[x]);
    }

    // Driver code
    
        var y = assignValue(3, 7, 0);
        document.write(y);

// This code is contributed by todaysgaurav 
</script>

Output

Time complexity : O(1)
Auxiliary Space : O(1)

Alternate Solution:

C++

// 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;
}

// C program to pick a value among two
// according to value of a third variable.
#include <stdio.h>
#include <stdbool.h>

// 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);
    printf("%d",y);
    return 0;
}

// This code is contributed by kothvvsaakash.