Java Program For Decimal to Hexadecimal Conversion (original) (raw)

Last Updated : 30 Jul, 2024

Given a decimal number N, convert N into an equivalent hexadecimal number i.e. convert the number with base value **10 to base value **16. The decimal number system uses 10 digits 0-9 and the Hexadecimal number system uses **0-9, A-F to represent any numeric value.

**Examples of Decimal to Hexadecimal Conversion

**Input : 10
**Output: A

**Input : 2545
**Output: 9F1

**Algorithm

  1. Store the remainder when the number is divided by 16 in an array.
  2. Divide the number by 16 now
  3. Repeat the above two steps until the number is not equal to 0.
  4. Print the array in reverse order now.

**Program for Decimal to Hexadecimal Conversion in Java

Java `

// Java program to convert Decimal Number // to Hexadecimal Number

// Importing input output classes import java.io.*;

// Main class public class GFG {

// Method 1
// To convert decimal to hexadecimal
static void decTohex(int n)
{
    // Creating an array to store octal number
    int[] hexNum = new int[100];

    // counter for hexadecimal number array
    int i = 0;
    while (n != 0) {

        // Storing remainder in hexadecimal array
        hexNum[i] = n % 16;
        n = n / 16;
        i++;
    }

    // Printing hexadecimal number array
    // in the reverse order
    for (int j = i - 1; j >= 0; j--) {
        if (hexNum[j] > 9)
            System.out.print((char)(55 + hexNum[j]));
        else
            System.out.print(hexNum[j]);
    }
}

// Method 2
// Main driver method
public static void main(String[] args)
{
    // Custom input decimal number
    // to be converted into hexadecimal number
    int n = 2545;

    // Calling the above Method1 over number 'n'
    // to convert this decimal into hexadecimal number
    decTohex(n);
}

}

`

The complexity of the above method:

**Time Complexity: O(log N)
**Auxiliary Space: O(1)

**Another Method Using Integer.toString()

The java.lang.Integer.toString( int a, int base) is an **inbuilt method in Java that is used to return a string representation of the argument in the base, specified by the second argument _base. If the radix/base is smaller than the Character.MIN_RADIX or larger than Character.MAX_RADIX, then the base 10 is used. The ASCII characters are used as digits: 0 to 9 and a to z.

**Syntax

public static String toString(int a, int base)

**Parameter: The method accepts two parameters:

**Return Value: The method returns a string representation of the specified argument in the specified base.

**Examples:

**Input: a = 71, base = 2
**Output: 1000111

**Input: a = 314, base = 16
**Output: 13a

**Java Program to Convert Decimal to Hexadecimal using Integer.toString() Method

Java `

// To convert Decimal to // Hexadecimal Number import java.util.*;

// Main driver method public class Main { public static void main(String[] args) { // Number in decimal int number = 2545;

    // output
    System.out.println(Integer.toString(number, 16));
}

}

`

Complexity of the above method

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

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