Question

What does the following code print? System.out.print("*"); System.out.print("***"); System.out.print("*****"); System.out.print("****"); System.out.println("**");

Short answer

The code prints '***************' in a single line followed by a newline character.

Step-by-step solution

Understanding the Java Print Statements

Analyze each Java System.out.print and System.out.println statement. The System.out.print command prints text without a newline at the end. In contrast, System.out.println prints text with a newline at the end. The code consists of a sequence of print statements that will output asterisks without line breaks until the last statement, which includes a line break.

Predicting the Concatenated Output

The print statements are concatenated one after the other in the order they are written. Combine each statement's output to predict the complete printed string: '*' followed by '***' followed by '*****' followed by '****' and finally '**' with a newline at the end due to println.

Result of the Printed Output

All the printed asterisks are concatenated into a single line because there are no newlines in between the print statements. The last print statement uses println, which will end the output with a newline. The printed text is '***************', where represents the newline character at the end.

Key concepts

System.out.print

In Java programming, System.out.print is a function that is used extensively for outputting data to the console. When you want to display text, numbers, or variables to the user without moving the cursor to the next line, System.out.print becomes your tool of choice. Imagine it as writing with a pen that won't lift off the paper until you're done; each print statement continues from where the last one ended.

For example, using consecutive System.out.print statements like in our exercise code results in a continuous stream of characters. It’s akin to writing sentences without any punctuation or spaces between words. This behavior is essential for building a line of output piece by piece, which is often a requirement in formatted text displays or when constructing a single string from multiple variables or constants.

System.out.println

The System.out.println function works similarly to System.out.print but with a key difference: it appends a newline character at the end of the text being printed. This means that after the function is called, the next output will start on a new line, similar to ending a sentence with a period before starting a new one.

Using System.out.println signals that you've completed a particular section of output. It organizes your data presentation by grouping related information together and segregating unrelated data. In our provided example, the use of System.out.println in the final print command ends our string of asterisks, pushing the cursor to the next line and serving as a full stop to our concatenated asterisk pattern.

String Concatenation in Java

String concatenation in Java is the process of joining multiple strings end-to-end to form a single string. It's like stringing beads on a necklace; each bead represents a piece of data, and when put together, they form a complete decoration.

In Java, the + operator is often used for this purpose. One can easily concatenate strings and variables to craft messages or compile data in human-readable form. For example, the code in the exercise demonstrates string concatenation implicitly. Each System.out.print statement outputs a string of asterisks that seamlessly connect, creating a longer string without any spaces. Understanding how concatenation works is essential for proper data display and manipulation in Java programming.

Java Newline Character

The newline character in Java is denoted by '' and is used to insert a line break in text. It's the invisible marker that signifies the end of a line, instructing the console to move the cursor down to start a new line, much like pressing 'Enter' on a keyboard when typing a document.

The System.out.println function automatically appends this newline character to the string it prints. In situations when you need to manually insert line breaks within a System.out.print function or within strings, you use the '' sequence. This control character is critical for formatting output, especially for creating multi-line structures or when a specific text layout is required.