Java Program to Convert Uppercase to Lowercase

Write a Java Program to Convert Uppercase to Lowercase with an example. In this section, we use built-in functions, loops, and ASCII values to get the result. In this Java Uppercase to Lowercase example, we use the built-in function toLowerCase() on the given string.

import java.util.Scanner;

public class UpperToLower1 {
	private static Scanner sc;
	public static void main(String[] args) {
		String uppStr;
		
		sc= new Scanner(System.in);

		System.out.print("\nEnter Uppercase String to convert =  ");
		uppStr = sc.nextLine();
	
		String uppStr2 = uppStr.toLowerCase();	
		System.out.println("\nThe Lowercase String  =  " + uppStr2);
	}
}

Here, in this Convert Uppercase to Lowercase example, first, we converted the uppStr string to upch character array using the toCharArray(). 

Next, we used a For loop to iterate the upch character array from start to end. Within the loop, we check whether the character at the index position is greater than or equal to A & less than or equal to Z. If it is True, we add 32 to the existing ASCII value. For example, A = 65, when we add 32, it becomes 97, and the ASCII value of a = 97.

import java.util.Scanner;

public class UpperToLower2 {
	private static Scanner sc;
	public static void main(String[] args) {
		String uppStr;
		int i;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter Uppercase String =  ");
		uppStr = sc.nextLine();
		
		char[] upch = uppStr.toCharArray();
		
		for(i = 0; i < upch.length; i++)
		{
			if(upch[i] >= 'A' && upch[i] <= 'Z') {
				upch[i] = (char) ((int)upch[i] + 32);;
			}
		}
		System.out.print("\nThe Lowercase String  =  ");
		for(i = 0; i < upch.length; i++) {
			System.out.print(upch[i]);
		}
	}
}

Please Enter Uppercase String =  LEARN JAVA

The Lowercase String  =  learn java

Java Program to Convert Uppercase to Lowercase Example 3

Here, we haven’t changed the uppStr string to a char array. Next, we used the charAt function in Java on the uppStr to get the character at the index position. Then, we assigned each character to lowStr2.

import java.util.Scanner;

public class UpperToLower3 {
	private static Scanner sc;
	public static void main(String[] args) {
		String uppStr, lowStr2 = "";
		int i;
		
		sc= new Scanner(System.in);

		System.out.print("\nEnter Uppercase String to convert =  ");
		uppStr = sc.nextLine();
		
		char ch;
		
		for(i = 0; i < uppStr.length(); i++)
		{
			if(uppStr.charAt(i) >= 'A' && uppStr.charAt(i) <= 'Z') {
				ch = (char) (uppStr.charAt(i) + 32);
			}
			else {
				ch = (char) (uppStr.charAt(i));
			}
			lowStr2 += ch;
		}
		System.out.print("\nThe Lowercase String  =  " + lowStr2);
	}
}

Enter Uppercase String to convert =  HAPPY PROGRAMMING

The Lowercase String  =  happy programming

In this Uppercase to Lowercase example, instead of assigning it to a new string, we print each character within the loop.

import java.util.Scanner;

public class UpperToLower4 {
	private static Scanner sc;
	public static void main(String[] args) {
		String uppStr;
		int i;
		
		sc= new Scanner(System.in);

		System.out.print("\nEnter Uppercase String to convert =  ");
		uppStr = sc.nextLine();
	
		System.out.print("\nThe Lowercase String =  ");
		for(i = 0; i < uppStr.length(); i++)
		{
			char ch = uppStr.charAt(i);
			if(ch >= 'A' && ch <= 'Z') {
				ch = (char) (ch + 32);
			}
			System.out.print(ch); // Str2 += ch;
		}
	}
}

Enter Uppercase String to convert =  HELLO WORLD

The Lowercase String =  hello world

In this Program to Convert Uppercase to Lowercase using ASCII Values, we compare the ASCII values instead of comparing characters.

import java.util.Scanner;

public class UpperToLower5 {
	private static Scanner sc;
	public static void main(String[] args) {
		String uppStr1, lowStr2 = "";
		int i;
		
		sc= new Scanner(System.in);

		System.out.print("\nEnter Uppercase String to convert =  ");
		uppStr1 = sc.nextLine();
	
		for(i = 0; i < uppStr1.length(); i++)
		{
			char ch = uppStr1.charAt(i);
			if(ch >= 65 && ch <= 90) {
				ch = (char) (ch + 32);
			}
			lowStr2 += ch;
		}
		System.out.print("\nThe Lowercase String =  " + lowStr2);
	}
}

Enter Uppercase String to convert =  JAVA PROGRAMMING

The Lowercase String =  java programming

In this code for Uppercase to Lowercase, we separated the logic using functions.

import java.util.Scanner;

public class UpperToLower6 {
	private static Scanner sc;
	public static void main(String[] args) {
		String uppStr, lowStr2;
		
		sc= new Scanner(System.in);

		System.out.print("\nEnter Uppercase String to convert =  ");
		uppStr = sc.nextLine();
		
		lowStr2 = toUpper(uppStr);
		System.out.print("\nThe Lowercase String =  " + lowStr2);
	}
	
	public static String toUpper(String uppStr) {
		String lowStr2 = "";
		
		for(int i = 0; i < uppStr.length(); i++)
		{
			char ch = uppStr.charAt(i);
			if(ch >= 65 && ch <= 90) {
				ch = (char) (ch + 32);
			}
			lowStr2 += ch;
		}
		return lowStr2;
	}
}

Enter Uppercase String to convert =  30 SEP JAVA CODING!

The Lowercase String =  30 sep java coding!