From 498b2b96484764de8820949eae7c250526216179 Mon Sep 17 00:00:00 2001 From: catalin-burcea Date: Thu, 8 Aug 2019 21:46:06 +0300 Subject: [PATCH] create triangles with for loops - examples --- algorithms-miscellaneous-3/pom.xml | 13 +++ .../printtriangles/PrintTriangleExamples.java | 49 ++++++++++ .../PrintTriangleExamplesUnitTest.java | 93 +++++++++++++++++++ 3 files changed, 155 insertions(+) create mode 100644 algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamples.java create mode 100644 algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamplesUnitTest.java diff --git a/algorithms-miscellaneous-3/pom.xml b/algorithms-miscellaneous-3/pom.xml index 3cebdd09acdd..802cf7432090 100644 --- a/algorithms-miscellaneous-3/pom.xml +++ b/algorithms-miscellaneous-3/pom.xml @@ -30,6 +30,19 @@ guava ${guava.version} + + + org.apache.commons + commons-lang3 + 3.8.1 + + + + pl.pragmatists + JUnitParams + 1.1.0 + test + diff --git a/algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamples.java b/algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamples.java new file mode 100644 index 000000000000..a67c54a92260 --- /dev/null +++ b/algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamples.java @@ -0,0 +1,49 @@ +package com.baeldung.algorithms.printtriangles; + +import org.apache.commons.lang3.StringUtils; + +public class PrintTriangleExamples { + + public static String printARightAngledTriangle(int N) { + StringBuilder result = new StringBuilder(); + for (int r = 1; r <= N; r++) { + for (int j = 1; j <= r; j++) { + result.append("*"); + } + result.append(System.lineSeparator()); + } + return result.toString(); + } + + public static String printAnIsoscelesTriangle(int N) { + StringBuilder result = new StringBuilder(); + for (int r = 1; r <= N; r++) { + for (int sp = 1; sp <= N - r; sp++) { + result.append(" "); + } + for (int c = 1; c <= (r * 2) - 1; c++) { + result.append("*"); + } + result.append(System.lineSeparator()); + } + return result.toString(); + } + + public static String printAnIsoscelesTriangleUsingSubstring(int N) { + StringBuilder result = new StringBuilder(); + String helperString = StringUtils.repeat(' ', N - 1) + StringUtils.repeat('*', N * 2 - 1); + + for (int r = 0; r < N; r++) { + result.append(helperString.substring(r, N + 2 * r)); + result.append(System.lineSeparator()); + } + return result.toString(); + } + + public static void main(String[] args) { + System.out.println(printARightAngledTriangle(5)); + System.out.println(printAnIsoscelesTriangle(5)); + System.out.println(printAnIsoscelesTriangleUsingSubstring(5)); + } + +} \ No newline at end of file diff --git a/algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamplesUnitTest.java b/algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamplesUnitTest.java new file mode 100644 index 000000000000..6fa6584b8eb4 --- /dev/null +++ b/algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/printtriangles/PrintTriangleExamplesUnitTest.java @@ -0,0 +1,93 @@ +package com.baeldung.algorithms.printtriangles; + +import junitparams.JUnitParamsRunner; +import junitparams.Parameters; +import org.junit.Test; +import org.junit.runner.RunWith; + +import static org.junit.Assert.assertEquals; + +@RunWith(JUnitParamsRunner.class) +public class PrintTriangleExamplesUnitTest { + + private static Object[][] rightAngledTriangles() { + String expected0 = ""; + + String expected2 = "*" + System.lineSeparator() + + "**" + System.lineSeparator(); + + String expected5 = "*" + System.lineSeparator() + + "**" + System.lineSeparator() + + "***" + System.lineSeparator() + + "****" + System.lineSeparator() + + "*****" + System.lineSeparator(); + + String expected7 = "*" + System.lineSeparator() + + "**" + System.lineSeparator() + + "***" + System.lineSeparator() + + "****" + System.lineSeparator() + + "*****" + System.lineSeparator() + + "******" + System.lineSeparator() + + "*******" + System.lineSeparator(); + + return new Object[][] { + { 0, expected0 }, + { 2, expected2 }, + { 5, expected5 }, + { 7, expected7 } + }; + } + + @Test + @Parameters(method = "rightAngledTriangles") + public void whenPrintARightAngledTriangleIsCalled_ThenTheCorrectStringIsReturned(int nrOfRows, String expected) { + String actual = PrintTriangleExamples.printARightAngledTriangle(nrOfRows); + + assertEquals(expected, actual); + } + + private static Object[][] isoscelesTriangles() { + String expected0 = ""; + + String expected2 = " *" + System.lineSeparator() + + "***" + System.lineSeparator(); + + String expected5 = " *" + System.lineSeparator() + + " ***" + System.lineSeparator() + + " *****" + System.lineSeparator() + + " *******" + System.lineSeparator() + + "*********" + System.lineSeparator(); + + String expected7 = " *" + System.lineSeparator() + + " ***" + System.lineSeparator() + + " *****" + System.lineSeparator() + + " *******" + System.lineSeparator() + + " *********" + System.lineSeparator() + + " ***********" + System.lineSeparator() + + "*************" + System.lineSeparator(); + + return new Object[][] { + { 0, expected0 }, + { 2, expected2 }, + { 5, expected5 }, + { 7, expected7 } + }; + } + + @Test + @Parameters(method = "isoscelesTriangles") + public void whenPrintAnIsoscelesTriangleIsCalled_ThenTheCorrectStringIsReturned(int nrOfRows, String expected) { + String actual = PrintTriangleExamples.printAnIsoscelesTriangle(nrOfRows); + + assertEquals(expected, actual); + } + + @Test + @Parameters(method = "isoscelesTriangles") + public void whenPrintAnIsoscelesTriangleUsingSubstringIsCalled_ThenTheCorrectStringIsReturned(int nrOfRows, String expected) { + String actual = PrintTriangleExamples.printAnIsoscelesTriangleUsingSubstring(nrOfRows); + + assertEquals(expected, actual); + } + +}