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Write program to reverse a String without using reverse() method in Java?
You can reverse a String in several ways, without using the reverse() function.
Using recursion − Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function. You can reverse a string using recursive function as shown in the following program.
Example
import java.util.Scanner;
public class StringReverse {
public static String reverseString(String str){
if(str.isEmpty()){
return str;
}else{
return reverseString(str.substring(1))+str.charAt(0);
}
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter a String value: ");
String str = sc.next();
String result = StringReverse.reverseString(str);
System.out.println(result);
}
}Output
Enter a String value: Tutorialspoint tniopslairotuT
Converting to byte/character array: You can get a byte or, character array using the getBytes() or, toCharArray() methods respectively.
To reverse a given String
- convert it into an array.
- Reverse the elements of the array.
- Create another String using the resultant array.
Example
import java.util.Scanner;
public class StringReverse {
public static String reverseString(String str){
//Converting to character array
char ch[] = str.toCharArray();
int n = ch.length;
char result[] = new char[n];
for(int i = 0; i<ch.length; i++) {
result[n-1] = ch[i];
n = n - 1;
}
return new String(result);
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter a String value: ");
String str = sc.next();
String result = StringReverse.reverseString(str);
System.out.println(result);
}
}Output
Enter a String value: Tutorialspoint tniopslairotuT
Updated on: 02-Aug-2019
4K+ Views
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