Java: Check whether the first instance of a given character is immediately followed by the same character in a given string

Last update on May 21 2025 12:50:10 (UTC/GMT +8 hours)

98. Check Repeated Character at First Instance

Write a Java program to check whether the first instance of a given character is immediately followed by the same character in a given string.

Visual Presentation:

Sample Solution:

Java Code:

import java.util.*;

// Define a class named Main
public class Main {
  
  // Method to check if 'z' appears twice in succession in the string
  boolean appearTwice(String stng) {
    int i = stng.indexOf("z"); // Get the index of the first occurrence of 'z'
    if (i == -1) return false; // If 'z' is not found, return false
    
    if (i + 1 >= stng.length()) return false; // If 'z' is at the end of the string, return false
    
    // Check if the character after the first 'z' is also 'z'
    return stng.substring(i + 1, i + 2).equals("z");
  }

  // Main method to execute the program
  public static void main(String[] args) {
    Main m = new Main(); // Create an instance of the Main class

    String str1 = "fizzez"; // Given string
    // Display the given string and whether 'z' appears twice respectively
    System.out.println("The given string is: " + str1);
    System.out.println("Is 'z' appear twice respectively? " + m.appearTwice(str1));
  }
}

Sample Output:

The given string is: fizzez
Is 'z' appear twice respectively? true

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to determine if the first occurrence of a target character is immediately repeated in the string.
• Write a Java program to check if the first instance of a given letter is directly duplicated.
• Write a Java program to verify if the first appearance of a specified character is immediately followed by the same character.
• Write a Java program to locate the first instance of a character and test if the subsequent character is identical.

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