Multiplique cualquier número por 4 usando el operador bit a bit

Somos un Número n y nuestra tarea es multiplicar el número por 4 usando el Operador bit a bit.
Ejemplos: 
 

Input : 4
Output :16

Input :5
Output :20

Explicación Caso 1: – n=4 el binario de 4 es 100 y ahora cambia dos bits a la derecha, luego 10000 ahora el número es 16 que se multiplica 4*4=16 ans. 
Enfoque :- (n<<2) desplazar dos bits a la derecha
 

// C++ program to multiply a number with
// 4 using Bitwise Operator
#include <bits/stdc++.h>
using namespace std;
 
// function the return multiply a number
//  with 4 using bitwise operator
int multiplyWith4(int n)
{
    // returning a number with multiply
    // with 4 using2 bit shifting right
    return (n << 2);
}
 
// derive function
int main()
{
    int n = 4;
    cout << multiplyWith4(n) << endl;
    return 0;
}

// Java program to multiply a number
// with 4 using Bitwise Operator
 
class GFG {
     
// function the return
// multiply a number
// with 4 using bitwise
// operator
static int multiplyWith4(int n)
{
     
    // returning a number
    // with multiply with
    // 4 using 2 bit shifting
    // right
    return (n << 2);
}
 
// Driver Code
public static void main(String[] args)
{
    int n = 4;
    System.out.print(multiplyWith4(n));
}
}
 
// This code is contributed by Smitha.

# Python 3 program to multiply
# a number with 4 using Bitwise
# Operator
 
# function the return multiply
# a number with 4 using bitwise
# operator
def multiplyWith4(n):
 
    # returning a number with
    # multiply with 4 using2
    # bit shifting right
    return (n << 2)
 
# derive function
n = 4
print(multiplyWith4(n))
 
# This code is contributed
# by Smitha

// C# program to multiply a number
// with 4 using Bitwise Operator
using System;
 
class GFG {
     
// function the return
// multiply a number
// with 4 using bitwise
// operator
static int multiplyWith4(int n)
{
     
    // returning a number
    // with multiply with
    // 4 using 2 bit shifting
    // right
    return (n << 2);
}
 
// Driver Code
public static void Main(String[] args)
{
    int n = 4;
    Console.Write(multiplyWith4(n));
}
}
 
// This code is contributed by Smitha.

<?php
// PHP program to multiply
// a number with 4 using
// Bitwise Operator
 
// function the return
// multiply a number
// with 4 using bitwise
// operator
function multiplyWith4($n)
{
     
    // returning a number
    // with multiply with
    // 4 using2 bit
    // shifting right
    return ($n << 2);
}
 
    // Driver Code
    $n = 4;
    echo multiplyWith4($n),"\n";
 
// This code is contributed by Ajit.
?>

<script>
// javascript program to multiply a number
// with 4 using Bitwise Operator  
// function the return
// multiply a number
// with 4 using bitwise
// operator
function multiplyWith4(n)
{
     
    // returning a number
    // with multiply with
    // 4 using 2 bit shifting
    // right
    return (n << 2);
}
 
// Driver Code
var n = 4;
document.write(multiplyWith4(n));
 
// This code is contributed by Amit Katiyar
</script>

Producción :- 
 

16

Generalización: en general, podemos multiplicar con una potencia de 2 usando operadores bit a bit. Por ejemplo, supongamos que deseamos multiplicar por 16 (que es 2 ⁴ ), podemos hacerlo desplazando a la izquierda por 4.