update .gitignore

Week8/Assignment8/.classpath

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-14">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

Week8/Assignment8/.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>Assignment8</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

Week8/Assignment8/.settings/org.eclipse.jdt.core.prefs

@@ -0,0 +1,14 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=14
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=14
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
+org.eclipse.jdt.core.compiler.release=enabled
+org.eclipse.jdt.core.compiler.source=14

Week8/Assignment8/numbers.txt

@@ -0,0 +1,100 @@
+84
+44
+73
+52
+49
+23
+53
+66
+52
+94
+93
+32
+3
+94
+3
+77
+7
+64
+86
+13
+10
+24
+42
+73
+63
+27
+59
+1
+13
+10
+79
+62
+16
+92
+90
+83
+83
+34
+18
+47
+72
+29
+1
+90
+71
+0
+99
+30
+66
+9
+10
+12
+58
+19
+15
+92
+74
+14
+10
+62
+36
+71
+23
+7
+26
+39
+21
+8
+15
+79
+94
+73
+8
+37
+44
+47
+39
+6
+93
+72
+21
+0
+65
+84
+64
+43
+13
+74
+91
+81
+54
+79
+66
+66
+61
+48
+26
+6
+34
+95

Week8/Assignment8/src/module-info.java

@@ -0,0 +1,2 @@
+module Assignment8 {
+}

Week8/Assignment8/src/partA/IsReverse.java

@@ -0,0 +1,37 @@
+//This code is written by Siwat Sirichai
+package partA;
+
+import java.util.Arrays;
+
+public class IsReverse {
+
+	public static boolean isReverse(int[] a, int[] b) {
+		if (a==null&&b==null)return true; //Special Case #1: if a and b is null, result: true, return right away to prevent NullPointer exception.
+		if((a==null&&b!=null)||(a!=null&&b==null))return false; //Special Case #2: if only one of a or b is null, result: false, return right away to prevent NullPointer exception.
+		if (a.length != b.length)return false; //Special Case #3: if the length of a and b is not equal, result: false, return right away to prevent ArrayIndexoutofBound exception.
+		for(int i = 0;i<a.length;i++)if(a[i]!=b[a.length-i-1])return false; //This is compare the first element of a with the last element of b, then second first of a and second last of b, so on...
+		return true;//If none of the condition are met (both a and b is not null), the two array are the reverse of each other
+	}
+
+	public static void main(String[] args) {
+		int[] a = { 1, 2, 2, 3, 4, 5 };
+		int[] b = { 5, 4, 3, 2, 2, 1 };
+		int[] c = { 1, 2, 0, 3, 4, 5 };
+		int[] d = { 1, 2, 2, 3, 4, 5, 0 };
+		int[] e = { 0, 5, 4, 3, 2, 2, 1 };
+		int[] f = null;
+		int[] g = null;
+
+		System.out.println("isReverse(a,b):" + isReverse(a, b) + ", expected to be true");
+		System.out.println("isReverse(b,c):" + isReverse(b, c) + ", expected to be false");
+		System.out.println("isReverse(a,c):" + isReverse(a, c) + ", expected to be false");
+		System.out.println("isReverse(d,e):" + isReverse(d, e) + ", expected to be true");
+		System.out.println("isReverse(e,d):" + isReverse(e, d) + ", expected to be true");
+		System.out.println("isReverse(d,b):" + isReverse(b, d) + ", expected to be false");
+		System.out.println("isReverse(f,g):" + isReverse(f, g) + ", expected to be true");
+		System.out.println("isReverse(f,a):" + isReverse(f, a) + ", expected to be false");
+		System.out.println("isReverse(a,f):" + isReverse(a, f) + ", expected to be false");
+
+	}
+
+}

Week8/Assignment8/src/partA/package-info.java

@@ -0,0 +1 @@
+package partA;

Week8/Assignment8/src/partB/Replace.java

@@ -0,0 +1,56 @@
+//This code is written by Siwat Sirichai
+package partB;
+public class Replace {
+
+	public static int[] replace(int[] a, int v, int v2) {
+		if (a==null)return a; //If a is a null pointer, return immediately to prevent a NullPointerException
+		for(int i = 0; i < a.length;i++) //loop from 0 to the length of array a, number of completed iteration is stored in i (type int)
+			if(a[i]==v)a[i]=v2; //if the value of a at index i is equal to v, replace it with v2
+		return a; //Return the replaced array a
+
+	}
+	
+	public static void printArray(int[] a) {
+		if(a==null) {
+			System.out.println(); //Create a newline to make the format looks uniform
+			return; //If a is a null pointer, return immediately to prevent a NullPointerException
+		}
+		//NOTE: return; (a return statement without a return value) in a method with no return type will break out of the method.
+		for(int i = 0;i<a.length;i++) { //loop from 0 to the length of array a, number of completed iteration is stored in i (type int)
+			System.out.print(a[i]); //print out the value of array a at index i
+			if(i<a.length-1)System.out.print(","); //print out a comma if the printed digit before it is not the last digit (last digit does not need a comma)
+		}
+		System.out.println(); //Create a newline to make the format looks uniform
+	}
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		int[] a = { 1, 2, 3, 1, 5, 4, 1, 2, 3, 1 };
+		int[] b = { 1, 5, 5, 1, 4, 5, 4, 2, 1, 5, 5, 2};
+		int[] b2 = { 1, 5, 5, 1, 4, 5, 4, 2, 1, 5, 5, 2};
+		int[] c = null;
+		int[] d = { 1, 2, 3, 4}; 
+
+		System.out.print("Printing array a: ");  printArray(a);
+		System.out.print("Printing array b: ");  printArray(b);
+		System.out.print("Printing array b2: ");  printArray(b2);
+		System.out.print("Printing array c: ");  printArray(c);
+		System.out.print("Printing array d: ");  printArray(d);
+
+		System.out.println("Now calling replace in each!");
+		replace(a,1,55);
+		replace(b,5,66);
+		replace(b2,4,77);
+		replace(c,1,5);
+		replace(d,5,7);
+
+		System.out.println("Printing result of each replace!");
+		System.out.print("Printing array a, replacing 1 with 55: ");  printArray(a);
+		System.out.print("Printing array b, replacing 5 with 66: ");  printArray(b);
+		System.out.print("Printing array b2, replacing 4 with 77: ");  printArray(b2);
+		System.out.print("Printing array c, replacing 1 with 5: ");  printArray(c);
+		System.out.print("Printing array d, replacing 5 with 7: ");  printArray(d);
+
+	}
+
+}

Week8/Assignment8/src/partB/package-info.java

@@ -0,0 +1 @@
+package partB;

Week8/Assignment8/src/partC/CountNumbers.java

@@ -0,0 +1,31 @@
+//This code is written by Siwat Sirichai
+package partC;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.Scanner;
+public class CountNumbers {
+
+	public static void main(String[] args) {
+		try { //Since java.io.File throws FileNotFoundException, a try-catch block is neccessary.
+			Scanner sc = new Scanner(new File("numbers.txt")); //This create a scanner with file "number.txt" as an input
+			int length = 0; //define array length initialy at zero
+			for(length = 0;sc.hasNextInt();length++)sc.nextInt(); //Use File Scanner to find the number of elements in the file
+			int[] int_array = new int[length]; //Create an array with length number of elements
+			sc = new Scanner(new File("numbers.txt")); //Send the Scanner's cursor to the top of the file
+			for(int i = 0;i<int_array.length;i++)int_array[i]=sc.nextInt(); //populate the array with the file's value
+			System.out.println("The number of integers greater than 25: "+greater(int_array,25));
+			System.out.println("The number of integers greater than 25: "+greater(int_array,50));
+			System.out.println("The number of integers greater than 25: "+greater(int_array,75));
+		} catch(FileNotFoundException e) {
+			System.out.println("File \"numbers.txt\" is not found in the current directory!"); //If no fie named numbers.txt is found, show "File "numbers.txt" is not found in the current directory!" and exit the program with exit code 0
+			System.exit(0);
+		}
+
+	}
+	public static int greater(int[] a,int v) {
+		int count = 0; //Create an int name count to store the number of numbers that are greater than a at all indexes
+		for(int val : a)if(val>v)count++;//This is called a for-each loop, it will loop for a.length iteration, 
+		return count;
+	}
+
+}

Week8/Assignment8/src/partC/package-info.java

@@ -0,0 +1 @@
+package partC;

Week8/Assignment8/src/partD/InsertArray.java

@@ -0,0 +1,60 @@
+//This code is written by Siwat Sirichai
+package partD;
+import partB.Replace;
+//Utilizing the method arraycopy(Array a,int a_start_pos, Array b,int b_start_pos, length)
+//This is kinda complicated, diagram attached.
+public class InsertArray {
+	public static void arraycopy(int[] a, int apos,int[] b, int bpos, int length) {
+		for(int i=0;i<length;i++) b[i+bpos] = a[i+apos];
+	}
+	public static int[] insert(int[] a, int[] b, int pos) {
+		int[] result = new int[a.length+b.length]; //Create an array with length of a+b
+		if (pos<=0){ //If pos <= 0, just put a b before a
+			arraycopy(b, 0, result, 0, b.length);
+			arraycopy(a, 0, result, b.length, a.length);
+		}
+		else if (pos>=a.length-1) { //If pos => a.length just put a before b
+			arraycopy(a, 0, result, 0, a.length);
+			arraycopy(b, 0, result, a.length, b.length);
+		}
+		else {
+			arraycopy(b, 0, result, pos, b.length); //put in b first
+			arraycopy(a, 0, result, 0, pos); //put the first part of a in (part before b)
+			arraycopy(a, pos, result, pos+b.length ,a.length-pos); //put the second part of a in (part after b)
+		}
+		return result;
+	}
+	
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		int[] a = { 1, 2, 3, 4};
+		int[] b = { 5, 6, 7};
+		int[] c = { 8, 9, 10, 11, 12}; 
+
+		System.out.print("Printing array a: ");  Replace.printArray(a);
+		System.out.print("Printing array b: ");  Replace.printArray(b);
+		System.out.print("Printing array c: ");  Replace.printArray(c);
+
+		System.out.println("Now calling inserts!");
+		System.out.println("------------------------");
+		int[] d = insert(a,b,1); 
+		int[] e = insert(a,b,4); //ERROR
+		int[] f = insert(b,a,0);
+		int[] g = insert(c,a,3);
+		int[] h = insert(c,a,-1);
+		int[] i = insert(c,a,7);  //ERROR
+
+		System.out.print("Printing array a, expecting {1,2,3,4} : ");  Replace.printArray(a);
+		System.out.print("Printing array b, expecting {5,6,7} : ");  Replace.printArray(b);
+		System.out.print("Printing array c, expecting {8,9,10,11,12} : ");  Replace.printArray(c);
+		System.out.print("Printing array d, expecting {1,5,6,7,2,3,4} : ");  Replace.printArray(d);
+		System.out.print("Printing array e, expecting {1,2,3,4,5,6,7} : ");  Replace.printArray(e);
+		System.out.print("Printing array f, expecting {1,2,3,4,5,6,7}: ");  Replace.printArray(f);
+		System.out.print("Printing array g, expecting {8,9,10,1,2,3,4,11,12} : ");  Replace.printArray(g);
+		System.out.print("Printing array h, expecting {1,2,3,4,8,9,10,11,12} : ");  Replace.printArray(h);
+		System.out.print("Printing array i, expecting {8,9,10,11,12,1,2,3,4} : ");  Replace.printArray(i);
+
+	}
+
+}

Week8/Assignment8/src/partD/package-info.java

@@ -0,0 +1 @@
+package partD;