Question

How to remove a bit from a number and shift all bits to the right to fill the gap in Go

Answer 1

package main

import (
    "fmt"
    "strings"
)

// Removes the bit at the given position and shifts all higher bits right.
func removeBitAndShift(number int, position int) int {
    /*
        number = 22 (10110)
        position = 2 (0 = LSB)

        Bits: 1 0 1 1 0
                  ^ remove this bit

        left  = bits above removed bit
        right = bits below removed bit

        result = (left << position) | right
    */

    left := number >> (position + 1)          // bits above removed bit
    right := number & ((1 << position) - 1)   // bits below removed bit

    return (left << position) | right         // merge shifted left + right
}

// Prints a 32-bit binary representation of an integer.
func printBinary(value int) {
    /*
        Uses:
            fmt.Sprintf("%b", value) → binary string
            pad to 32 bits using strings.Repeat
            group into 4-bit chunks for readability
    */

    binary := fmt.Sprintf("%b", value)
    if len(binary) < 32 {
        binary = strings.Repeat("0", 32-len(binary)) + binary
    }

    // Group into 4-bit chunks
    for i := 0; i < 32; i += 4 {
        fmt.Print(binary[i:i+4], " ")
    }
    fmt.Println()
}

func main() {
    number := 22
    position := 2 // remove bit 2 (0 = LSB)

    fmt.Println("Original number in binary:")
    printBinary(number)

    result := removeBitAndShift(number, position)

    fmt.Println()
    fmt.Println("Number after removing bit", position, "and shifting remaining bits:")
    printBinary(result)

    fmt.Println()
    fmt.Println("Result as integer:", result)
}



/*
run:

Original number in binary:
0000 0000 0000 0000 0000 0000 0001 0110 

Number after removing bit 2 and shifting remaining bits:
0000 0000 0000 0000 0000 0000 0000 1010 

Result as integer: 10

*/

 

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