Week4-1

Calculator.java

+package fi.utu.mskwon;
+
+class Calculator {
+    private double result;
+
+    public Calculator() {
+        reset();
+    }
+
+    public void reset() {
+        this.result = 0;
+    }
+
+    public double getResult() {
+        return this.result;
+    }
+
+    public void add(int value) {
+        this.result += value;
+    }
+
+    public void subtract(int value) {
+        this.result -= value;
+    }
+
+    public void multiply(int value) {
+        this.result *= value;
+    }
+
+    public void exponent(int value) {
+        double base = this.result;
+        if (value > 0) {
+            for (int i = 1; i < value; i++) {
+                base *= base;
+            }
+            this.result = base;
+        } else if (value < 0) {
+            for (int i = 1; i < -value; i++) {
+                base *= base;
+            }
+            this.result = 1/base;
+        } else {
+            this.result = 1;
+        }
+    }
+}
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CalculatorTest.java

+package fi.utu.mskwon;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class CalculatorTest {
+
+    @Test
+    void reset() {
+        Calculator calculator = new Calculator();
+        assertEquals(0, calculator.getResult());
+    }
+
+    @Test
+    void getResult() {
+        Calculator calculator = new Calculator();
+        assertEquals(0, calculator.getResult());
+    }
+
+    @Test
+    void add() {
+        Calculator calculator = new Calculator();
+        calculator.add(10);
+        calculator.add(-5);
+        assertEquals(5, calculator.getResult());
+    }
+
+    @Test
+    void subtract() {
+        Calculator calculator = new Calculator();
+        calculator.add(10);
+        calculator.subtract(5);
+        assertEquals(5, calculator.getResult());
+    }
+
+    @Test
+    void multiply() {
+        Calculator calculator = new Calculator();
+        calculator.add(5);
+        calculator.multiply(2);
+        calculator.multiply(-3);
+        assertEquals(-30, calculator.getResult());
+    }
+
+    @Test
+    void exponent() {
+        Calculator calculator = new Calculator();
+        calculator.add(5);
+        calculator.exponent(2);
+        assertEquals(25, calculator.getResult());
+        calculator.reset();
+        calculator.add(5);
+        calculator.exponent(-2);
+        assertEquals((double) 1/25, calculator.getResult());
+        calculator.reset();
+        calculator.add(5);
+        calculator.exponent(0);
+        assertEquals(1, calculator.getResult());
+    }
+}
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