In this challenge, you will practice manipulating strings by extracting and transforming specific parts of a Java `String`. This exercise will help you reinforce your understanding of **reference types** and common string operations, which are essential skills when working with user input or formatting output.

Suppose you are given a person's full name in the format `First Last` (for example, `John Doe`). Your task is to extract the first letter of each name part, convert them to uppercase, and print them together as the person's initials. If the input is `John Doe`, the output should be `JD`. You will use string methods such as `split`, `charAt`, and `toUpperCase` to accomplish this.

package com.example;

import static org.junit.jupiter.api.Assertions.assertEquals;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

public class MainTest {

    @Test
    @DisplayName("Returns initials for John Doe")
    void testReturnsInitialsJohnDoe() {
        String result = Main.getInitials("John Doe");
        assertEquals("JD", result, "Expected initials 'JD' for input 'John Doe', but got: '" + result + "'");
    }

    @Test
    @DisplayName("Returns initials for Alice Smith")
    void testReturnsInitialsAliceSmith() {
        String result = Main.getInitials("Alice Smith");
        assertEquals("AS", result, "Expected initials 'AS' for input 'Alice Smith', but got: '" + result + "'");
    }

    @Test
    @DisplayName("Returns initials for mary ann")
    void testReturnsInitialsMaryAnn() {
        String result = Main.getInitials("mary ann");
        assertEquals("MA", result, "Expected initials 'MA' for input 'mary ann', but got: '" + result + "'");
    }

    @Test
    @DisplayName("Returns initials for Bob O'Reilly")
    void testReturnsInitialsBobOReilly() {
        String result = Main.getInitials("Bob O'Reilly");
        assertEquals("BO", result, "Expected initials 'BO' for input 'Bob O'Reilly', but got: '" + result + "'");
    }
}


MainTest.java

A comprehensive course on Java data types, covering primitives, reference types, type conversion, and practical applications. Designed for learners with basic Java syntax knowledge.

Explore Java's built-in primitive data types, their properties, and how to use them effectively.

Delve into Java's reference types, focusing on Strings and arrays, and how they differ from primitives.

Learn about type casting, automatic conversions, and the use of wrapper classes for primitives.

Challenge: String Manipulation

解答