PPractick

The problem

You're starting a series of pattern exercises, and the first one is the simplest possible shape: an n × n square of stars. It's the base every other pattern builds on. The outer loop controls the rows, the inner loop controls what goes in each row, and here every row is identical. Getting this one right (with the right number of rows and columns, and nothing extra at the ends) sets up the mental model for the next twenty patterns.

Example for n = 3:

***
***
***

Function signature

vector<string> squarePattern(int n);  // n rows, each with n stars

Test cases

Input n	Output rows	Explanation
1	"*"	One row, one star
3	"***", "***", "***"	Three identical rows
5	five rows of "*****"	Rows and columns both equal n

(Confirm: stars are printed without separators; some judges, such as GeeksforGeeks, expect a space after each star, which only changes what is appended in the inner loop.)

How interviewers phrase it

• "Print an N × N square of stars."
• Almost always the first of a series: after this the interviewer asks for a triangle, then a pyramid, checking how you adapt the inner loop.
• Used in campus assessments to check basic nested-loop control.

Clarifying questions to ask

1. Should the stars be separated by spaces?
2. Print directly, or return the rows?
3. What should happen for N = 0?

Follow-ups to expect

1. "What does each loop control?"
2. "How would you print a rectangle of R rows and C columns?"
3. "How would you make it hollow?"
4. "What's the complexity?"

Related questions

• Easy and Medium Easy
• Hard Easy
• Pattern 2 Easy
• Pattern 3 Easy
• Pattern 4 Easy
• Pattern 5 Easy

All 474 dsa interview questions

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