diff --git a/.DS_Store b/.DS_Store index 27875fa6e..f28585d78 100644 Binary files a/.DS_Store and b/.DS_Store differ diff --git a/CountChar.java b/CountChar.java new file mode 100644 index 000000000..dfdc0684d --- /dev/null +++ b/CountChar.java @@ -0,0 +1,42 @@ +import java.util.Scanner; + + +/** + * @author Kyler Smith, 2017 + * + * Implementation of a character count. + * (Slow, could be improved upon, effectively O(n). + * */ + +public class CountChar { + + public static void main(String[] args) { + Scanner input = new Scanner(System.in); + System.out.print("Enter your text: "); + String str = input.nextLine(); + + System.out.println("There are " + CountCharacters(str) + " characters."); + } + + + + /** + * @param str: String to count the characters + * + * @return int: Number of characters in the passed string + * */ + + public static int CountCharacters(String str) { + + int count = 0; + + if(str.isEmpty() || str == null) + return -1; + + for(int i = 0; i < str.length(); i++) + if(!Character.isWhitespace(str.charAt(i))) + count++; + + return count; + } +} diff --git a/data_structures/Matrix/Matrix.java b/data_structures/Matrix/Matrix.java new file mode 100644 index 000000000..652a4e83b --- /dev/null +++ b/data_structures/Matrix/Matrix.java @@ -0,0 +1,197 @@ +/** +* Matrix data-type. +* +* @author Kyler Smith, 2017 +*/ + + +public class Matrix { + + public static void main(String[] args) { + + int[][] data1 = new int[0][0]; + int[][] data2 = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}; + int[][] data3 = {{1, 4, 7}, {2, 5, 8}, {3, 6, 9}}; + + Matrix m1 = new Matrix(data1); + Matrix m2 = new Matrix(data2); + Matrix m3 = new Matrix(data3); + + System.out.println("m1 --> Rows: " + m1.getRows() + " Columns: " + m1.getColumns()); + System.out.println("m2 --> Rows: " + m2.getRows() + " Columns: " + m2.getColumns()); + System.out.println("m3 --> Rows: " + m3.getRows() + " Columns: " + m3.getColumns()); + + //check for reference issues + System.out.println("m2 -->\n" + m2); + data2[1][1] = 101; + System.out.println("m2 -->\n" + m2); + + //test equals + System.out.println("m2==null: " + m2.equals(null)); //false + System.out.println("m3==\"MATRIX\": " + m2.equals("MATRIX")); //false + System.out.println("m2==m1: " + m2.equals(m1)); //false + System.out.println("m2==m2: " + m2.equals(m2)); //true + System.out.println("m2==m3: " + m2.equals(m3)); //false + + //test operations (valid) + System.out.println("2 * m2:\n" + m2.scale(2)); + System.out.println("m2 + m3:\n" + m2.plus(m3)); + System.out.println("m2 - m3:\n" + m2.minus(m3)); + } + + + /** + * Data needs to be a deep copy as not to change the original state. + */ + private int[][] data; + + /** + * Constructor for the matrix takes in a 2D array + * + * @param pData + */ + public Matrix(int[][] pData) { + + /** Make a deep copy of the data */ + if(pData.length != 0) { + int[][] newData = new int[pData.length][pData[0].length]; + + for(int i = 0; i < pData.length; i++) + for(int j = 0; j < pData[0].length; j++) + newData[i][j] = pData[i][j]; + + this.data = newData; + } else { + this.data = null; + } + } + + /** + * Returns the element specified by the given location + * + * @param x : x cooridinate + * @param y : y cooridinate + * @return int : value at location + */ + public int getElement(int x, int y) { + return data[x][y]; + } + + /** + * Returns the number of rows in the Matrix + * + * @return rows + */ + public int getRows() { + if(this.data == null) + return 0; + + return data.length; + } + + /** + * Returns the number of rows in the Matrix + * + * @return columns + */ + public int getColumns() { + if(this.data == null) + return 0; + return data[0].length; + } + + /** + * Returns this matrix scaled by a factor. That is, computes sA where s is a + * constant and A is a matrix (this object). + * + * @param scalar : value to scale by + * @return A new matrix scaled by the scalar value + */ + public Matrix scale(int scalar) { + + int[][] newData = new int[this.data.length][this.data[0].length]; + + for (int i = 0; i < this.getRows(); ++i) + for(int j = 0; j < this.getColumns(); ++j) + newData[i][j] = this.data[i][j] * scalar; + + return new Matrix(newData); + } + + /** + * Adds this matrix to another matrix. + * + * @param other : Matrix to be added + * @return addend + */ + public Matrix plus(Matrix other) throws RuntimeException { + + int[][] newData = new int[this.data.length][this.data[0].length]; + + if(this.getRows() != other.getRows() || this.getColumns() != other.getColumns()) + throw new RuntimeException("Not the same size matrix."); + + for (int i = 0; i < this.getRows(); ++i) + for(int j = 0; j < this.getColumns(); ++j) + newData[i][j] = this.data[i][j] + other.getElement(i, j); + + return new Matrix(newData); + } + + /** + * Subtracts this matrix from another matrix. + * + * @param other : Matrix to be subtracted + * @return difference + */ + public Matrix minus(Matrix other) throws RuntimeException { + + int[][] newData = new int[this.data.length][this.data[0].length]; + + if(this.getRows() != other.getRows() || this.getColumns() != other.getColumns()) + throw new RuntimeException("Not the same size matrix."); + + for (int i = 0; i < this.getRows(); ++i) + for(int j = 0; j < this.getColumns(); ++j) + newData[i][j] = this.data[i][j] - other.getElement(i, j); + + return new Matrix(newData); + } + + /** + * Checks if the matrix passed is equal to this matrix + * + * @param other : the other matrix + * @return boolean + */ + public boolean equals(Matrix other) { + return this == other; + } + + /** + * Returns the Matrix as a String in the following format + * + * [ a b c ] ... + * [ x y z ] ... + * [ i j k ] ... + * ... + * + * @return Matrix as String + * TODO: Work formatting for different digit sizes + */ + public String toString() { + String str = ""; + + for(int i = 0; i < this.data.length; i++) { + str += "[ "; + for(int j = 0; j < this.data[0].length; j++) { + str += data[i][j]; + str += " "; + } + str += "]"; + str += "\n"; + } + + return str; + } +} diff --git a/ft.java b/ft.java index 843f4a559..815dbd292 100644 --- a/ft.java +++ b/ft.java @@ -1,19 +1,17 @@ import java.util.Scanner; - class FloydTriangle - { - public static void main(String[] args) - { -Scanner sc = new Scanner(System.in); -System.out.println("Enter the number of rows which you want in your Floyd Triangle: "); -int r = sc.nextInt(); -int n=0; -for(int i=0; i<r; i++) -{ -for(int j=0; j<=i; j++) -{ -System.out.print(++n+" "); + + +class FloydTriangle { + public static void main(String[] args) { + Scanner sc = new Scanner(System.in); + System.out.println("Enter the number of rows which you want in your Floyd Triangle: "); + int r = sc.nextInt(), n = 0; + + for(int i=0; i < r; i++) { + for(int j=0; j <= i; j++) { + System.out.print(++n + " "); + } + System.out.println(); + } + } } -System.out.println(); -} -} -} \ No newline at end of file