I have set myself the task of trying to effectively diagnose a Bug in this piece of code, which has been written in JavaScript. the problem. How does a coder who has just started to learn coding, use 'variable watching', 'compiler warnings' and a 'unit test' for this objective? Here is the piece of code I am referring to:
JavaScript:
import java.util.Scanner;
public class StudentVersion {
public static void main(String[] args) {
boolean run = true;
String choice;
do {
choice = displayMenu();
if (choice.equals("x")){
run = false;
}
else if (choice.equals("1")){
double x = getNumber(1);
double y = getNumber(2);
int total = sumMethod(x,y);
display(totl);
run = checkFinish();
}
else if (choice.equals("2")){
double x = getNumber(1);
double y = getNumber(2);
double total = subtractMethod(x,y);
display(total);
run = checkFinish();
}
else if (choice.equals("3")){
double x = getNumber(1);
double y = getNumber(2);
double total = multiplymethod(x,y);
display(total);
run = checkFinish();
}
else (choice.equals("4")){
double x = getNumber(1);
double y = getNumber(2);
double total = divideMethod(x,y);
display(total);
run = checkFinish();
}
else {
System.out.println("Entry not recognised, please try again...");
}
} while (run);
}
public static double getNumber(int count){
boolean numberWrong = true;
while (numberWrong) {
if (count == 1) {
System.out.print("Enter 1st number: ");
} else {
System.out.println("Enter 2nd number: ");
}
Scanner reader = new Scanner(System.in);
try {
double x = reader.nextLine();
return x;
} catch (Exception e){
System.out.println("Number not recognised, please try again.");
}
}
return 0;
}
public static String displayMenu(){
System.out.println(" Calculator Menu");
System.out.println("1. Add numbers");
System.out.println("2. Subtract numbers");
System.out.println("3. Multiply numbers");
System.out.println("4. Divide numbers");
System.out.println("x. Exit program");
System.out.println();
Scanner reader = new Scanner(System.in);
System.out.print("Enter option (1,2,3,4,x): ");
return reader.nextLine();
}
public static boolean checkFinish(){
Scanner reader = new Scanner(System.in);
boolean check = true;
System.out.print("Have you finished (y/n): ");
String ans = reader.nextLine().trim().toLowerCase();
if (ans.equals("y")){
return false;
}
else{
return true;
}
}
public static double sumMethod(double n, double m){
System.out.println("When adding the numbers");
return (n * m);
}
public static double subtractMethod(double n, double m){
System.out.println("When subtracting the numbers");
return (n - m);
}
public static double multiplyMethod(double n, double m){
System.out.println("When multiplying the numbers");
return (n * m);
}
public static double divideMethod(double n, double m){
System.out.println("When dividing the numbers");
return ((double)n / m);
}
public static void display(double sum){
System.out.println("The answer is: " + sum)
}
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