C PROGRAMMING PROGRAM • PATTERN PROGRAMS

Print a Diamond Star Pattern

Learn how to print a diamond star pattern using a clear C program.

IntermediateNested loopsRows and columnsPattern

PROBLEM UNDERSTANDING

Input and expected output

Sample input

Sample output

  *
 ***
*****
 ***
  *

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int rows;

    printf("Enter half-height: ");
    scanf("%d", &rows);
    for (int row = 1; row <= rows; row++) {
        for (int space = row; space < rows; space++) printf(" ");
        for (int star = 1; star <= 2 * row - 1; star++) printf("*");
        printf("\n");
    }
    for (int row = rows - 1; row >= 1; row--) {
        for (int space = rows; space > row; space--) printf(" ");
        for (int star = 1; star <= 2 * row - 1; star++) printf("*");
        printf("\n");
    }
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

  *
 ***
*****
 ***
  *

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Combine an increasing centred pyramid with a decreasing one.
Display the computed result.

Combine an increasing centred pyramid with a decreasing one.

EFFICIENCY

Time and space complexity

Time complexity

O(n²)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

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Use the correct format specifier for every variable.

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Initialize variables before using their values.

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Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.