2 Language Fundamentals

The following program will compile and run without errors:

package com.acme; // Correct ordering of package and import statements.

import java.util.*;

public class Exercise1 {
    int counter; // This is rather useless

    public static void main(String[] args) { // Correct main signature
        Exercise1 instance = new Exercise1();
        instance.go();
    }

    public void go() {
        int sum = 0;
        // We could just as well have written sum = 100
        // here and removed the if statement below.
        int i = 0;
        while (i<100) {
            if (i == 0) sum = 100;
            sum = sum + i;
            i++;
        }
        System.out.println(sum);
    }
}

The following program will compile and run without errors:

// Filename: Temperature.java
/* Identifiers and keywords in Java are case-sensitive. Therefore, the
   case of the file name must match the class name, the keywords must
   all be written in lowercase. The name of the String class has a
   capital S. The main method must be static and take an array of
   String objects as an argument. */
public class Temperature {
    public static void main(String[] args) {  // Correct method signature
        double fahrenheit = 62.5;
        // /* identifies the start of a "starred" comment.
        // */ identifies the end.
        /* Convert */
        double celsius = f2c(fahrenheit);
        // '' delimits character literals, "" delimits string literals
        System.out.println(fahrenheit + "F = " + celsius + "C");
    }

    static double f2c(double fahr) {          // Note parameter type
        return (fahr - 32) * 5 / 9;
    }
}