AP CSA 1.15 Exercise 1: Cut the String

Unit 1: Using Objects and Methods · Lesson 1.15 · Exercise 1

Cut the String

String Manipulation. Write real Java, run it, and submit it to be graded against hidden test cases.

Back to the Lesson 1.15 page All Unit 1 lessons

Why this one is worth doing

substring takes the first index and stops BEFORE the second. Off by one here is the most reliable way to lose a point on the exam, so this exercise makes you use it four different ways.

What to write

Read one word.
Print its length.
Print the first three characters using substring.
Print everything from index 2 onward using the one argument form of substring.
Print the index of the letter e, or -1 when there is not one.
Print the whole word in upper case.

Your program reads

A single word of at least three characters.

Your program prints

Five lines: the length, the first three characters, the tail from index 2, the index of e, and the word in upper case.

Worked examples

These are the cases you can see. There are more you cannot, and they use different values, so an answer that prints these numbers as constants will fail.

Example 1 input

computer

Example 1 output

8
com
mputer
6
COMPUTER

Example 2 input

javascript

Example 2 output

10
jav
vascript
-1
JAVASCRIPT

Your answer

Main.java

import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    String word = input.next();

    // Five lines.
  }
}

Input for the Run button

Run sends whatever is in the input box below. Submitting runs your program against every test case, including hidden ones with different input.

Stuck?

Hint 1

substring(0, 3) gives you characters 0, 1 and 2. The second number is where it stops, not the last one it keeps.

Hint 2

substring(2) with one argument runs to the end of the String.

Hint 3

indexOf returns -1 when the letter is not there, which is a value you print rather than an error you handle.

Where to go next

Rework the Lesson 1.15 page Pick another Unit 1 lesson

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