CSIT111/811 Lab Exercises

Lab week5

Objectives

• Java code analysis and debugging
• Data types, arithmetic expressions, Math methods
• Data type conversion
• Strings

Exercise 1:Analyse, compile and fix bugs in the following program

{`public class CircleBugs { 

public static void main(String[] args) {

double t = Double.parseDouble(args[0]); 

int r = Integer.parseInt(args[0]); 


 	 	 System.out.println("r = " + r + ",  t = " + t) 


 	 	 double c = 2 * Math.PI * r; 
	 	
double A = Math.PI * r * r; 


 	 	 double x = r * cos(t);  
	 	
double y = r * sin(t); 


 	 	 	 	 System.out.println("c = " + c ); 

System.out.println("A = " + A ); 

System.out.println("x = " + x + ", " + "y = " + y );  

} 

}
`}

After all errors are corrected, you would have the output as follows:

java CircleBugs 1.2 0.6 r = 1.2, t = 0.6 c = 7.5398223686155035 a = 4.523893421169302 x = 0.9904027378916139, y = 0.6775709680740424

Exercise 2: If you carefully look at the ASCII Character Table, you'll notice that the difference between uppercase and lowercase character codes is 32. Implement a program that

• Prompts the user to enter a lowercase character
• Reads the entered character
• Converts this lowercase character to the corresponding uppercase character - Displays the uppercase character

Exercise 3: Implement a program that:

• Prompts the user to enter a floating point number nA
• Calculates nB = nA⁵
• Displays nB with 1 decimal point precision if it is less than 199.0, otherwise it displays a constant value 199.0

When you implement this solution you can use only material covered in Lectures 1-4.

Exercise 4: Implement a program that:

• Reads a floating point number nA from the command line
• Calculates nB = e^na
• Coverts nb to an integer number discarding its decimal part
• Displays nB

When you implement this solution you can use only material covered in Lectures 1-4.

Exercise 5: Implement this simple program:

{`
import java.util.Scanner;

class InpTest

{
	 	 
public static void main( String[] args ) 

{ 

Scanner keyboard = new Scanner(System.in); 

	    
System.out.print("Enter a double: ");
 
double db = keyboard.nextDouble();
    
System.out.println("Input was: " + db); 

System.out.print("Enter an integer: "); 

int ia = keyboard.nextInt(); 

System.out.println("Input was: " + ia); 

}

} 
`}

The program works properly if your input is right. However, try to enter two (or more) double numbers before you press Enter.

• Explain why the program is not working properly with this input
• Try to implement a simple solution (doesn't need to be perfect) that proves your explanation