Print and println output in Kotlin - Step-by-Step Execution

Concept Flow - Print and println output

Start Program

↓

Call print()

↓

Output text without newline

↓

Call println()

↓

Output text with newline

↓

End Program

The program starts, prints text without moving to a new line, then prints text with a newline, and ends.

Execution Sample

Kotlin

fun main() {
    print("Hello, ")
    println("world!")
}

Prints 'Hello, ' without newline, then prints 'world!' with newline.

Execution Table

Step	Function Called	Output	Cursor Position After Output
1	print("Hello, ")	Hello,	After the comma and space, cursor stays on same line
2	println("world!")	world!	Cursor moves to start of next line

💡 Program ends after printing both outputs; cursor is at start of new line.

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
Output Stream	""	"Hello, "	"Hello, world!\n"	"Hello, world!\n"

Key Moments - 2 Insights

Why does print() not move to a new line after output?

Because print() outputs text exactly as given without adding a newline, as shown in step 1 of the execution_table where the cursor stays on the same line.

What does println() do differently from print()?

println() outputs the text and then adds a newline character, moving the cursor to the next line, as seen in step 2 of the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the cursor position after step 1?

A After the printed text on the same line

B At the start of the next line

C At the beginning of the output

D Cursor position is unchanged

💡 Hint

Check the 'Cursor Position After Output' column for step 1 in the execution_table.

At which step does the output move to a new line?

A Step 1

B Step 2

C Both steps

D Neither step

💡 Hint

Look at the 'Output' and 'Cursor Position' columns in the execution_table.

If we replace print() with println() in step 1, what changes in the output?

A Output stays on the same line

B No output is printed

C Output moves to a new line after step 1

D Output is printed twice

💡 Hint

Recall that println() adds a newline after printing, as shown in step 2.

Concept Snapshot

print(text): outputs text without moving to a new line
println(text): outputs text and moves cursor to next line
Use print() to continue on same line
Use println() to start new line after output

Full Transcript

This example shows how Kotlin's print() and println() functions work. First, print("Hello, ") outputs text without moving to a new line, so the cursor stays right after the comma and space. Then, println("world!") outputs text and moves the cursor to the next line by adding a newline character. This difference is important when formatting output. The execution table tracks each step's output and cursor position. The variable tracker shows how the output stream builds up. Remember, print() keeps output on the same line, println() moves to a new line after printing.

Practice

1. What is the main difference between print and println in Kotlin?

easy

A. print outputs only numbers; println outputs only text.

B. print adds a newline after output; println outputs text without a newline.

C. print outputs text without a newline; println adds a newline after output.

D. print is used for debugging; println is used for user messages.

Solution

1. Step 1: Understand print behavior

   print outputs text exactly as given and stays on the same line.

2. Step 2: Understand println behavior

   println outputs text and then moves the cursor to the next line.

3. Final Answer:

   print outputs text without a newline; println adds a newline after output. -> Option C

4. Quick Check:

   print no newline, println newline = A [OK]

Hint: Remember: println adds a line break, print does not [OK]

Common Mistakes:

• Confusing which function adds a newline
• Thinking print adds a newline
• Assuming println outputs only numbers

2. Which of the following is the correct syntax to print "Hello" and then move to a new line in Kotlin?

easy

A. println("Hello")

B. print("Hello")

C. println Hello

D. println["Hello"]

Solution

1. Step 1: Check syntax correctness

   Only println("Hello") uses correct function call syntax with parentheses and quotes.

2. Step 2: Verify output behavior

   println("Hello") prints "Hello" and moves to a new line automatically.

3. Final Answer:

   println("Hello") -> Option A

4. Quick Check:

   Correct syntax with println = A [OK]

Hint: Use parentheses and quotes exactly for print/println [OK]

Common Mistakes:

• Missing parentheses around arguments
• Using square brackets instead of parentheses
• Omitting quotes around strings

3. What will be the output of the following Kotlin code?

print("Hi")
println(" there")
print("Welcome")

medium

A. Hi there
Welcome

B. Hi
there
Welcome

C. Hi there Welcome

D. Hi there
Welcome

Solution

1. Step 1: Trace first print statement

   print("Hi") outputs "Hi" without newline.

2. Step 2: Trace println statement

   println(" there") outputs " there" and moves to next line.

3. Step 3: Trace last print statement

   print("Welcome") outputs "Welcome" on the new line.

4. Final Answer:

   Hi there Welcome -> Option D

5. Quick Check:

   print no newline, println newline = D [OK]

Hint: Remember print stays on line; println moves to next line [OK]

Common Mistakes:

• Assuming print adds newline
• Ignoring space in " there"
• Thinking all output is on one line

4. Identify the error in this Kotlin code snippet:

print("Hello")
println "World"

medium

A. Missing parentheses in println call

B. Missing quotes around Hello

C. print cannot be used without println

D. No error, code runs fine

Solution

1. Step 1: Check syntax of print statement

   print("Hello") is correct with parentheses and quotes.

2. Step 2: Check syntax of println statement

   println "World" is missing parentheses around the argument, which is required in Kotlin.

3. Final Answer:

   Missing parentheses in println call -> Option A

4. Quick Check:

   Function calls need parentheses = B [OK]

Hint: Always use parentheses for function calls in Kotlin [OK]

Common Mistakes:

• Omitting parentheses in function calls
• Thinking print needs println to work
• Confusing quotes usage

5. You want to print the numbers 1, 2, and 3 on the same line separated by spaces, then print "Done" on the next line. Which Kotlin code achieves this?

hard

A. print("1 2 3")
print("Done")

B. print("1 2 3")
println("Done")

C. print("1 ")
print("2 ")
print("3\n")
println("Done")

D. println("1")
println("2")
println("3")
print("Done")

Solution

1. Step 1: Print numbers on same line with spaces

   Using print("1 2 3") outputs "1 2 3" on the same line.

2. Step 2: Print "Done" on next line

   println("Done") prints "Done" and moves to the next line.

3. Final Answer:

   print("1 2 3") println("Done") -> Option B

4. Quick Check:

   Use print for same line, println for new line = A [OK]

Hint: Use print for same line, println to move to next line [OK]

Common Mistakes:

• Using println for each number causing new lines
• Using print after println without newline
• Adding \n inside print incorrectly