Here, we will implement a Java program to print the square star pattern. We will print the square star pattern with diagonals and without diagonals.
Example:
********************** * * * * * * * * * * * * **********************
Approach:
Step 1: Input number of rows and columns.
Step 2: For rows of rectangle run the outer loop from 1 to rows.
for (i = 1; i < = rows; i++)
Step 3: For the column of the rectangle run the inner loop from 1 to columns.
for (j = 1; j < = columns; j++)
Step 4: Print star for first or last row or for first or last column, otherwise print blank space.
Step 5: After printing all columns of a row, print the newline after the inner loop.
Example 1: Star square pattern without diagonals
Java
// Java Program to Print Square Pattern// Case 1: Hollow rectangle// Importing input output classesimport java.io.*;// Main classclass GFG { // Method 1 // To print hollow rectangle static void print_rectangle(int k, int l) { int a, b; // Nested for loops for iterations // Outer loop for rows for (a = 1; a <= k; a++) { // Inner loop for columns for (b = 1; b <= l; b++) { // Condition check using logical OR operator // over rows and columns positions // if found at circumference of rectangle if (a == 1 || a == k || b == 1 || b == l) // Print the star pattern System.out.print("*"); else // Rest inside square print the empty // spaces System.out.print(" "); } // By now we are done with only 1 row so // New line System.out.println(); } } // Method 2 // Main driver method public static void main(String args[]) { // Declaring and initializing rows and columns // For square row = columns // Custom input initialization values int rows = 8, columns = 22; // Calling the method1 to print hollow rectangle // pattern print_rectangle(rows, columns); }} |
********************** * * * * * * * * * * * * **********************
Time complexity: O(R*C) for given no of rows R and columns C
Auxiliary space: O(1) because it is using constant space
Now taking it a step further as in above we simply inserted empty spaces inside the rectangle. In mathematics, we already have come across diagonals, so we can print them too in the above case.
Example 2: Star square pattern with diagonals
Java
// Java Program to Print Square Star pattern// Case: Primary and secondary diagonal Rectangle Patternimport java.io.*;// Mai classclass GFG { // Method 1 // To print square with primary and secondary diagonal static void print_squaredi(int k) { int a, b; // Nested 2 for loops for Matrix printing // Outer loop for rows for (a = 1; a <= k; a++) { // Inner loop for columns for (b = 1; b <= k; b++) { // Condition check using OR operator where // 1. Printing star as per first 4 checks // on the circumference of rectangle // 2. Fifth check is for diagonals if (a == 1 || a == k || b == 1 || b == k || a == b || b == (k - a + 1)) // Print the star pattern System.out.print("*"); else // Print the white spaces System.out.print(" "); } // By now we are over with one row so // new line System.out.println(); } } // Method 2 // Main driver method public static void main(String args[]) { // This time taking square so only one variable // needs to be declared // Custom input entry int rows = 12; // calling the method1 to print // square pattern with diagonal print_squaredi(rows); }} |
************ ** ** * * * * * * * * * * * * * ** * * ** * * * * * * * * * * * * * ** ** ************
Time complexity: O(N2) where N is given input, no of rows
Auxiliary Space : O(1)
