Erster commit

Axel/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

Axel/.gitignore

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+/bin/

Axel/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>Axel</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>

Axel/resources/zahlen.csv

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+,,,,,,,,,
+1,,,,,,,,,
+123,,,,,,,,,
+,,,,,,,,,
+,,,,,,,,,=7*6
+,,,,,,,,,=3/2
+,,,,,,,,,
+,,,,,,,,,
+,=41+A2,,,,,,,,
+,,,,,,,,,

Axel/src/de/hs_mannheim/informatik/spreadsheet/Axel.java

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+package de.hs_mannheim.informatik.spreadsheet;
+
+import java.io.FileNotFoundException;
+
+/**
+ * Part of a simplified spreadsheet system for the PR1 programming lab at Hochschule Mannheim.
+ *
+ * @author  Oliver Hummel
+ */
+public class Axel {
+
+	public static void main(String[] args) throws FileNotFoundException {
+		Spreadsheet spr = new Spreadsheet(10,10);
+		
+		spr.put("A3", "123");
+		spr.put("A2", "1");
+		
+		spr.put("B9", "=41+A2");
+		spr.put("J5", "=7*6");
+		spr.put("J6", "=3/2");
+		
+		System.out.println(spr);
+		
+		spr.saveCsv("C:\\Users\\devra\\eclipse-workspace\\Axel\\resources\\zahlen.csv");
+		
+		// TODO: You might want to put "UI loop" for entering value and formulas here resp. in some UI methods.
+	}
+
+}

Axel/src/de/hs_mannheim/informatik/spreadsheet/Cell.java

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+package de.hs_mannheim.informatik.spreadsheet;
+
+/**
+ * Part of a simplified spreadsheet system for the PR1 programming lab at Hochschule Mannheim.
+ * A cell needs to be able to hold a formula and a value 
+ *
+ * @author  Oliver Hummel
+ */
+public class Cell {
+    private String formula = "";
+    private String value = "";
+    
+    public String getFormula() {
+        return formula;
+    }
+    
+    public void setFormula(String formula) {
+        if (!formula.isEmpty())
+            this.formula = formula.toUpperCase().substring(1);  // removes '=' at the beginning
+    }
+    
+    public String getValue() {
+        return value;
+    }
+    
+    public void setValue(String value) {
+        this.value = value;
+    }
+    
+    public String toString() {
+        return String.format("%4s", value);
+    }
+    
+    public boolean isEmpty() {
+        return value.isEmpty();
+    }
+    
+}

Axel/src/de/hs_mannheim/informatik/spreadsheet/Spreadsheet.java

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+package de.hs_mannheim.informatik.spreadsheet;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * A simplified spreadsheet class for the PR1 programming lab at Hochschule Mannheim.
+ * One aspect worth mentioning is that it only supports long numbers, not doubles.
+ *
+ * @author  Oliver Hummel
+ */
+public class Spreadsheet {
+	Cell[][] cells;
+
+	/**
+	 * Constructor that creates a Spreadsheet of size rows * cols.
+	 * @param rows number of rows
+	 * @param cols number of columns
+	 */
+	public Spreadsheet(int rows, int cols) {
+
+		// TODO limit the maximum size on 99 (1..99) rows and 26 (A..Z) columns
+
+		cells = new Cell[rows][cols];
+
+		for (int r = 0; r < rows; r++)
+			for (int c = 0; c < cols; c++)
+				cells[r][c] = new Cell();
+	}
+
+	// -----
+	// retrieve or change values of cells
+
+	private String get(int row, int col) {
+		return cells[row][col].getValue();
+	}
+
+	public String get(String cellName) {
+		cellName = cellName.toUpperCase();
+		return get(getRow(cellName), getCol(cellName));
+	}
+
+	private void put(int row, int col, String value) {
+		if (!value.startsWith("="))
+			cells[row][col].setValue(value);
+		else {
+			cells[row][col].setFormula(value);
+			evaluateCell(row, col);
+		}
+	}
+
+	public void put(String cellName, String value) {
+		cellName = cellName.toUpperCase();
+		put(getRow(cellName), getCol(cellName), value);
+	}
+
+	private int getCol(String cellName) {
+		return cellName.charAt(0) - 'A';
+	}
+
+	private int getRow(String cellName) {
+		return cellName.charAt(1) - '1';
+	}
+
+	// -----
+	// business logic
+
+	/**
+	 * A method for reading in data from a CSV file.
+	 * @param path The file to read.
+	 * @param separator The char used to split up the input, e.g. a comma or a semicolon.
+	 * @param starCellName The upper left cell where data from the CSV file should be inserted.
+	 * @return Nothing.
+	 * @exception IOException If path does not exist.
+	 */
+	public void readCsv(String path, char separator, String startCellName) throws FileNotFoundException {
+		// TODO: implement this
+	}
+
+	/**
+	 * A method for saving data to a CSV file.
+	 * @param path The file to write.
+	 * @return Nothing.
+	 * @exception IOException If path does not exist.
+	 */
+	public void saveCsv(String path) throws FileNotFoundException {
+		PrintWriter out = new PrintWriter(path);
+
+		for (Cell[] row : cells) {
+			for (Cell cell : row) {
+				if (!cell.getFormula().isEmpty())
+					out.print("=" + cell.getFormula());
+				else
+					out.print(cell.getValue());
+
+				if (cell != row[cells[0].length-1])
+					out.print(",");
+			}
+			out.println();
+		}
+
+		out.close();
+	}
+
+	/**
+	 * This method does the actual evaluation/calcluation of a specific cell
+	 * @param cellName the name of the cell to be evaluated
+	 * @return Nothing.
+	 */
+	private void evaluateCell(int row, int col) {
+		String formula = cells[row][col].getFormula();
+		String result = "";
+
+		if (formula.startsWith("SUMME("))  // e.g. SUMME(A3:A8)
+			result = "" + sum(formula.substring(6, 8), formula.substring(9, 11));  // TODO adapt to cells with two digits
+		else if (formula.startsWith("PRODUKT("))  // e.g. PRODUKT(A3:B9)
+			result = "TODO"; // TODO
+		else if (formula.startsWith("MITTELWERT("))  // e.g. MITTELWERT(A3:A5)
+			result = "TODO"; // TODO
+		else if (formula.startsWith("STABW("))  // e.g. STABW(C6:D8) -> Standardabweichung
+			result = "TODO"; // TODO
+		else if (formula.startsWith("MIN("))  // e.g. MIN(C13:H13) -> größter Wert
+			result = "TODO"; // TODO
+		else if (formula.startsWith("MAX("))  // e.g. MAX(A1:A10) -> Standardabweichung
+			result = "TODO"; // TODO
+		else if (!formula.isEmpty()) {
+			try {
+				result = "" + calculate(formula);
+			} catch(ArithmeticException ae) {
+				result = "exc.";
+			}
+		}
+
+		cells[row][col].setValue("" + result);
+	}
+
+	/**
+	 * Method for calculating the sum of a rectangular block of cells, such as from A1 to B3.
+	 * @param startCellName The name of the cell in the upper left corner of the rectangle.
+	 * @param endCellName The name of the cell in the lower right corner of the rectangle.
+	 * @return The sum calculated.
+	 */
+	private long sum(String startCellName, String endCellName) {
+		// TODO implement
+
+		return 0;
+	}
+
+	/**
+	 * This method calculates the result of a "normal" algebraic expression. It only needs to support
+	 * expressions like =B4 or =2+A3-B2, i.e. only with int numbers and other cells and with plus,
+	 * minus, times, split only. An expression always starts with either a number or a cell name. If it 
+	 * continues, it is guaranteed that this is followed by an operator and either a number or a 
+	 * cell name again. It is NOT required to implement dot before dash or parentheses in formulas.
+	 * @param formula The expression to be evaluated.
+	 * @return The result calculated.
+	 */
+	private long calculate(String formula) throws ArithmeticException {
+		Matcher m = Pattern.compile("([A-Z][0-9]*)|[-\\+\\*/]|[0-9]*").matcher(formula);
+
+		long res = 0;
+
+		// TODO implement
+
+		// uncomment the following to see an example how the elements of a formula can be accessed
+		while (m.find()) {        // m.find() must always be used before m.group()
+			String s = m.group();
+			if (!s.isEmpty()) {
+				System.out.println(s);
+			}
+		}
+
+		return res;
+	}
+
+	// -----
+
+	public String toString() {
+		StringBuilder sb = new StringBuilder();
+
+		sb.append("    ");
+		for (int i = 0; i < cells[0].length; i++) {
+			sb.append("  " + (char)('A'+ i) + "  | ");
+		}
+
+		int rc = 1;
+		for (Cell[] r : cells) {
+			sb.append(System.lineSeparator());
+			sb.append(String.format("%2s", rc++) + ": ");
+
+			for (Cell c : r) {
+				sb.append(c + " | ");
+			}
+
+		}
+		return sb.toString();
+	}
+
+}