Frequently Asked Java Program 22: Java Program to Trim Whitespace From String Without Using Trim Method
Hello Folks,
This interview question was asked in Deloitte.
Write a java program to Trim a given string without using inbuilt trim() method of String Class in Java.
“trim()” method of String class trims leading and trailing whitespace/s of given string. It does not remove whitespace between words. We need to write logic to do so.
Logic step by step:
- We need to find first index of non space char in given string from beginning. Say it First.
- We need to find first index of non space char in given string from end. Say it Last.
- Return a substring indexing from First till Last.
Detailed Explanation:
- Assume first char of given string is a non space char and set starting index of non space char as zero. Now check if it is really a non space char. If it it, finalize starting index as zero else increment index by one and repeat the same till you get a non space char.
- Assume last char of given string is a non space char and set last index of non space char as (Length of String-1). Now check if it is really a non space char. If it it, finalize end index as (Length of String-1) else decrement index by one and repeat the same till you get a non space char.
- Once Starting and Ending index are finalized, get the substring.
Java Program:
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package StringPrograms; import java.util.Scanner; public class TrimSpacesWithoutTrimMethod { public static String trimSpace(String str) { // Assume 0th index is non-space character int startNonSpaceIndex = 0; // Assume last index is non-space character int endNonSpaceIndex = str.length()-1; // Store length in a variable int strLength = str.length(); // Convert string into char array char[] val = str.toCharArray(); // Increment startNonSpaceIndex by one until you really find a non space char while (startNonSpaceIndex < strLength && val[startNonSpaceIndex] == ' ') { startNonSpaceIndex++; } // Decrement endNonSpaceIndex by one until you really find a non space char // Since we know starting index of a non space char, so we should not exceed // that which // is taking care by (startNonSpaceIndex < endNonSpaceIndex) while (startNonSpaceIndex < endNonSpaceIndex && val[endNonSpaceIndex] == ' ') { endNonSpaceIndex--; } // Now you have actual starting and ending index of non space char in given // string. return str.substring(startNonSpaceIndex, endNonSpaceIndex+1); } public static void main(String[] args) { // User input to trim spaces Scanner sc = new Scanner(System.in); System.out.println("Please enter the string to trim spaces:"); String userInput = sc.nextLine(); sc.close(); System.out.println("You entered with spaces: \"" + userInput+"\""); System.out.println("String after trimming space: \""+trimSpace(userInput) +"\""); } } |
Output:
Please enter the string to trim spaces:
Make Selenium Easy
You entered with spaces: " Make Selenium Easy "
String after trimming space: "Make Selenium Easy"
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Please enter the string to trim spaces:
Make Selenium Easy
You entered with spaces: " Make Selenium Easy "
String after trimming space: "Make Selenium Easy"
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#HappyCoding
Author: Amod Mahajan
A software Tester who is paid to judge products developed by others. Currently getting paid in American Dollars. Writing technical posts and creating YouTube videos are my hobbies.
public class MainClass {
public static void main(String[] args) {
String str = ” Make Selenium Easy “;
int startIndex = 0;
int lastIndex = 0;
char[] charray = str.toCharArray();
for (int i = 0; i 0; i–) {
if (charray[i] != ‘ ‘) {
lastIndex = i;
break;}
}
System.out.println(str.substring(startIndex, lastIndex+1));
}
}
public class MainClass {
public static void main(String[] args) {
String str = ” Make Selenium Easy “;
int startIndex = 0;
int lastIndex = 0;
char[] charray = str.toCharArray();
for (int i = 0; i 0; i–) {
if (charray[i] != ‘ ‘) {
lastIndex = i;
break;}
}
System.out.println(str.substring(startIndex, lastIndex+1));
}
}