3.10. Coding Practice

The following code should generate a random number and print if it is evenly divisible by 2. However, the code has an error and always prints “Your number is even”, even if the random number is odd. Fix the code so that it only prints the message when the number is even.

The following code should check your guess against the answer and print that it is too low, correct, or too high. However, the code has errors. Fix the code so that it compiles and runs correctly.

The following code should print “You can go out” if you have done your homework and cleaned your room. However, the code has errors. Fix the code so that it compiles and runs correctly.

The following code should print if x is in the range of 0 to 10 (including 0 and 10). However, the code has errors. Fix the errors so that the code runs as intended.

The following code should print if x is less than 0, equal to 0, or greater than 0. Finish it to work correctly.

public class Test1
{
    public static void main(String[] args)
    {
        int x = -3;
        if (x > 0)
            System.out.println("x is less than 0");

}

}
====
import static org.junit.Assert.*;
  import org.junit.*;;
  import java.io.*;

public class RunestoneTests extends CodeTestHelper
  {
      @Test
      public void testMain() throws IOException
      {
        String output = getMethodOutput("main");
        String expect = "x is less than 0";
        boolean passed = getResults(expect, output, "Expected output from main if x = -3");
        assertTrue(passed);
      }

@Test
      public void testCheckCodeContains()
      {
          boolean outputLess = checkCodeContains("if (x < 0)");
          assertTrue(outputLess);
      }
      @Test
      public void testCheckCodeContains2()
      {
          String code = getCode();
          boolean ifGreater = code.contains("if (x > 0)");
          boolean ifEqual = code.contains("if (x == 0)");
          boolean passed = getResults("Test if x greater than 0 or test if x is equal to 0", "Greater than: " + ifGreater + ", Equal to: " + ifEqual, "Test if x greater than 0 or if x equal to 0", ifGreater || ifEqual );
          assertTrue(passed);
      }
  }

Finish the code below so that it prints You can go out if you have a ride or if you can walk and otherwise prints You can't go out. Use a logical or to create a complex conditional.

public class Test1
{
    public static void main(String[] args)
    {
        boolean canWalk = true;
        boolean haveRide = false;

}
}
====
import static org.junit.Assert.*;
  import org.junit.*;;
  import java.io.*;

public class RunestoneTests extends CodeTestHelper
  {
      @Test
      public void testCheckCodeContains()
      {
          boolean output1 = checkCodeContains("print statement You can go out", "System.out.println(\"You can go out\")");
          assertTrue(output1);
      }

@Test
      public void testCheckCodeContains2()
      {
          boolean output2 = checkCodeContains("print statement You can't go out", "System.out.println(\"You can't go out\")");
          assertTrue(output2);
      }

@Test
      public void testCheckCodeContains3()
      {
          boolean output3 = checkCodeContains("or", "||");
          assertTrue(output3);
      }

@Test
      public void testChangedCode() {
          String origCode = "public class Test1 { public static void main(String[] args) { boolean canWalk = true; boolean haveRide = false; } }";

boolean changed = codeChanged(origCode);

assertTrue(changed);

}
  }

Finish the code below to print you can go out if you don’t have homework and you have done the dishes.

public class Test1
{
    public static void main(String[] args)
    {
        boolean haveHomework = false;
        boolean didDishes = true;

}
}
====
import static org.junit.Assert.*;
  import org.junit.*;;
  import java.io.*;

public class RunestoneTests extends CodeTestHelper
  {
      @Test
      public void testCheckCodeContains()
      {
          boolean output1 = checkCodeContains("print statement You can go out", "System.out.println(\"You can go out\")");
          assertTrue(output1);
      }

@Test
      public void testCheckCodeContains2()
      {
          boolean output2 = checkCodeContains("and", "&&");
          assertTrue(output2);
      }

@Test
      public void testCheckCodeContains3()
      {
          boolean output2 = checkCodeContains("not", "!");
          assertTrue(output2);
      }

@Test
      public void testChangedCode() {
          String origCode = "public class Test1 { public static void main(String[] args) { boolean haveHomework = false; boolean didDishes = true; } }";
          boolean changed = codeChanged(origCode);
          assertTrue(changed);
      }
  }

Finish the following code so that it prints You have a fever if your temperature is above 100 and otherwise prints You don't have a fever.

public class Test1
{
    public static void main(String[] args)
    {
        double temp = 103.5;
    }
}
====
import static org.junit.Assert.*;
  import org.junit.*;;
  import java.io.*;

public class RunestoneTests extends CodeTestHelper
  {
      @Test
      public void testCheckCodeContains()
      {
          boolean output1 = checkCodeContains("print statement You have a fever", "System.out.println(\"You have a fever\")");
          assertTrue(output1);
      }

@Test
      public void testCheckCodeContains2()
      {
          boolean output2 = checkCodeContains("print statement You don't have a fever", "System.out.println(\"You don't have a fever\")");
          assertTrue(output2);
      }

@Test
      public void testCheckCodeContains3()
      {
          boolean output4 = checkCodeContains("if statement for temp greater than 100", "if (temp > 100)");
          assertTrue(output4);
      }

@Test
      public void testChangedCode() {
          String origCode = "public class Test1 { public static void main(String[] args) { double temp = 103.5; } }";
          boolean changed = codeChanged(origCode);
          assertTrue(changed);
      }
  }

Finish the code to print It is freezing if the temperature is below 30, It is cold if it is below 50, It is nice out if it is below 90, or It is hot using nested if else statements.

public class Test1
{
    public static void main(String[] args)
    {
        int temp = 100;

}
}
====
import static org.junit.Assert.*;
  import org.junit.*;;
  import java.io.*;

public class RunestoneTests extends CodeTestHelper
  {
       @Test
      public void testCountIfs()
      {
          String code = getCode();
          int num = countOccurences(code, "if");
          boolean passed = num >= 3;

getResults("3+", "" + num, "Number of if statements", passed);
          assertTrue(passed);
      }

@Test
      public void testCountElses()
      {
          String code = getCode();
          int num = countOccurences(code, "else");
          boolean passed = num >= 3;

getResults("3+", "" + num, "Number of else statements", passed);
          assertTrue(passed);
      }

@Test
      public void testCountPrints()
      {
          String code = getCode();
          int num = countOccurences(code, "System.out.print");
          boolean passed = num >= 4;

getResults("4+", "" + num, "Number of print statements", passed);
          assertTrue(passed);
      }

@Test
      public void testMain() throws IOException
      {
        String expect = "It is hot";
        String output = getMethodOutput("main");
        boolean passed = getResults(expect, output, "Prints It is hot if temp = 100");
        assertTrue(passed);
      }
       @Test
      public void testChangedCode() {
          String origCode = "public class Test1 { public static void main(String[] args) {  int temp = 100; } }";
          boolean changed = codeChanged(origCode);
          assertTrue(changed);
      }
  }

Finish the code below to print your grade based on your score. The score is an A if you scored 92 or higher, a B if you scored 82 to 91, a C if you scored 72 to 81, a D if you scored a 62 to 71, or an E.

public class Test1
{
    public static void main(String[] args)
    {
        double score = 67;

}
}
====
import static org.junit.Assert.*;
  import org.junit.*;;
  import java.io.*;

public class RunestoneTests extends CodeTestHelper
  {
    @Test
      public void testChangedCode() {
          String origCode = "public class Test1 { public static void main(String[] args) {        double score = 67; } }";

boolean changed = codeChanged(origCode);

assertTrue(changed);

}

@Test
      public void testCheckCodeContains()
      {

boolean outputA = checkCodeContains("print statement - A", "System.out.println(\"A\")");
         assertTrue(outputA);

}

@Test
      public void testCheckCodeContains2()
      {
        boolean outputB = checkCodeContains("print statement - B", "System.out.println(\"B\")");
        assertTrue(outputB);
      }

@Test
      public void testCheckCodeContains3()
      {
        boolean outputC = checkCodeContains("print statement - C", "System.out.println(\"C\")");
        assertTrue(outputC);
      }

@Test
      public void testCheckCodeContains4()
      {
        boolean outputD = checkCodeContains("print statement - D", "System.out.println(\"D\")");
        assertTrue(outputD);
      }

@Test
      public void testCheckCodeContains5()
      {
        boolean outputE = checkCodeContains("print statement - E", "System.out.println(\"E\")");
        assertTrue(outputE);
      }

@Test
      public void testCheckCodeContains6(){
        boolean output = checkCodeContains("if you scored 92 or higher", "if (score >= 92)");
        assertTrue(output);
      }

@Test
      public void testCheckCodeContains7(){
        boolean output = checkCodeContains("else if you scored 82 or higher", "else if (score >= 82)");
        assertTrue(output);
      }

@Test
      public void testCheckCodeContains8(){
        boolean output = checkCodeContains("else if you scored 72 or higher", "else if (score >= 72)");
        assertTrue(output);
      }

@Test
      public void testCheckCodeContains9(){
        boolean output = checkCodeContains("else if you scored 62 or higher", "else if (score >= 62)");
        assertTrue(output);
      }
  }

Before you keep reading...

Before you keep reading...

3.10. Coding Practice¶