Pattern Printing In 5 languages | Go | Java | Python | Ruby | TypeScript

pattern.go

/*
go version go1.17 linux/amd64
RUN CODE HERE https://go.dev/play/
simply copy and paste -> click "run"
*/
package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(upperStarPattern() + lowerStarPattern())
}

/*Helper function to create row*/
func createPatternRow(nStars int, s string) string {
	numOfSpaces := 9 - (2 * nStars)

	starStr := strings.Repeat("*", nStars)
	spaceStr := strings.Repeat(" ", numOfSpaces)

	s += starStr + spaceStr + starStr + "\n"
	return s
}

/*Upper half of star pattern*/
func upperStarPattern() string {
	// R1 is all stars
	s := strings.Repeat("*", 9) + "\n"
	// loop from R2 -> R5
	i := 0
	for i < 4 {
		s = createPatternRow(4-i, s)
		i++
	}
	return s
}

/*Lower half of star pattern*/
func lowerStarPattern() string {
	s := ""
	// loop from R6 -> R8
	i := 0
	for i < 3 {
		s = createPatternRow(i+2, s)
		i++
	}
	// R9 is all "*"
	s += strings.Repeat("*", 9)
	return s
}

pattern.java

/**
 * openjdk 11.0.13 2021-10-19
 * pattern printing
 * RUN CODE HERE
 * https://www.jdoodle.com/online-java-compiler/
 * copy-paste
 * select jdk 11 and press "execute"
 */
public class pattern {
    public static void main(String[] args) {
        System.out.println(upperStarPattern() + lowerStarPattern());
    }

    private static String createPatternRow(int nStars, String s) {
        int numOfSpace = 9 - (2 * nStars);

        String starStr = "*".repeat(nStars);
        String spaceStr = " ".repeat(numOfSpace);

        s = s.concat(starStr + spaceStr + starStr + "\n");
        return s;
    }

    /**Upper half of star pattern */
    private static String upperStarPattern() {
        // R1 is all stars
        String s = "*".repeat(9) + "\n";
        // loop from R2 -> R5
        for (int i = 0; i < 4; i++) {
            s = createPatternRow(4-i, s);
        }
        return s;
    }

    /**Lower half of star pattern */
    private static String lowerStarPattern() {
        String s = "";
        // loop from R6 -> R8
        for (int i = 0; i < 3; i++) {
            s = createPatternRow(i+2, s);
        }
        // R9 is all *
        s = s.concat("*".repeat(9));
        return s;
    }
}

pattern.py

"""pattern to print
*********
**** ****
***   ***
**     **
*       *
**     **
***   ***
**** ****
*********
"""
def createPatternRow(nStars: int, s: str, end: str='\n') -> str:
    """Helper function to create row"""
    numOfSpaces = 9 - (2 * nStars)

    starStr = nStars * "*"
    spaceStr = numOfSpaces * " "

    s += starStr + spaceStr + starStr + end
    return s

def upperStarPattern() -> str:
    """Upper half of star pattern"""
    # R1 is all stars
    s = "*" * 9 + "\n"
    # loop from R2 -> R5
    for i in range(4):
        s = createPatternRow(4 - i, s)
    return s

def lowerStarPattern() -> str:
    """Lower half of star pattern"""
    s = ""
    # loop from R6 -> R8
    for i in range(3):
        s = createPatternRow(i + 2, s)       
    # R9 is all "*"
    s += "*" * 9
    return s

print(upperStarPattern() + lowerStarPattern())

pattern.rb

# Ruby
# RUN CODE HERE https://try.ruby-lang.org/
# copy paste
# then press "run"

# Helper function to create row
def createPatternRow(nStars, s, endStr="\n")
    numOfSpaces = 9 - (2 * nStars)

    starStr = "*" * nStars
    spaceStr = " " * numOfSpaces

    s += (starStr + spaceStr + starStr + endStr)
    return s
end

# Upper half of star pattern
def upperStarPattern    
    # R1 is all stars
    s = "*" * 9 + "\n"
    # loop from R2 -> R5
    (0..3).each do |i|
        s = createPatternRow(4-i, s)
    end
    
    return s
end

# Lower half of star pattern
def lowerStarPattern    
    s = ""
    # loop from R6 -> R8
    (0..2).each do |i|
        s = createPatternRow(i + 2, s)
    end
    # R9 is all "*"
    s += "*" * 9
    return s
end

puts(upperStarPattern() + lowerStarPattern())

pattern.ts

/*
TypeScript Version 4.5.5
RUN CODE HERE https://www.typescriptlang.org/play
copy paste, and press run
[no need to set the version]
*/

/**Helper function to create row */
function createPatternRow(nStars: number, s: string, end: string = "\n"): string {
    let numOfSpaces = 9 - (2 * nStars);

    let starStr = "*".repeat(nStars);
    let spaceStr = " ".repeat(numOfSpaces);

    s = s.concat(starStr, spaceStr, starStr, end);
    return s;
}

/**Upper half of star pattern */
function upperStarPattern(): string {
    // R1 is all stars
    let s = "*".repeat(9) + "\n";
    // loop from R3 -> R5
    for (let i = 0; i < 4; i++) {
        s = createPatternRow(4 - i, s);
    }
    return s;
}

/**Lower half of star pattern */
function lowerStarPattern(): string {
    let s = "";
    // loop from R6 -> R8
    for (let i = 0; i < 3; i++) {
        s = createPatternRow(i + 2, s);
    }
    // R9 is all stars
    s += "*".repeat(9);
    return s;
}

console.log("\n\r" + upperStarPattern() + lowerStarPattern() + "\n");