Programming Fundamentals/Variable Examples Java
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Overview
[edit | edit source]The following examples demonstrate data types, arithmetic operations, and input in Java.
Data Types
[edit | edit source] // This program demonstrates variables, literal constants, and data types.
public class Main {
public static void main(String[] args) {
int i;
double d;
String s;
boolean b;
i = 1234567890;
d = 1.23456789012345;
s = "string";
b = true;
System.out.println("Integer i = " + i);
System.out.println("Double d = " + d);
System.out.println("String s = " + s);
System.out.println("Boolean b = " + b);
}
}
Output
[edit | edit source]Integer i = 1234567890 Double d = 1.23456789012345 String s = string Boolean b = true
Discussion
[edit | edit source]Each code element represents:
//
begins a commentpublic class DataTypes
begins the Data Types program{
begins a block of codepublic static void main(String[] args)
begins the main functionint i
defines an integer variable named i;
ends each line of Java codedouble d
defines a double floating-point variable named dstring s
defines a string variable named sboolean b
defines a Boolean variable named bi = , d = , s =, b =
assign literal values to the corresponding variablesSystem.out.println
calls the standard output print line function}
ends a block of code
Arithmetic
[edit | edit source] // This program demonstrates arithmetic operations.
public class Main {
public static void main(String[] args) {
int a;
int b;
a = 3;
b = 2;
System.out.println("a = " + a);
System.out.println("b = " + b);
System.out.println("a + b = " + (a + b));
System.out.println("a - b = " + (a - b));
System.out.println("a * b = " + a * b);
System.out.println("a / b = " + a / b);
System.out.println("a % b = " + (a % b));
}
}
Output
[edit | edit source]a = 3 b = 2 a + b = 5 a - b = 1 a * b = 6 a / b = 1 a % b = 1
Discussion
[edit | edit source]Each new code element represents:
+, -, *, /, and %
represent addition, subtraction, multiplication, division, and modulus, respectively.
Temperature
[edit | edit source] // This program converts an input Fahrenheit temperature to Celsius.
import java.util.*;
public class Main {
private static Scanner input = new Scanner(System.in);
public static void main(String[] args) {
double fahrenheit;
double celsius;
System.out.println("Enter Fahrenheit temperature:");
fahrenheit = input.nextDouble();
celsius = (fahrenheit - 32) * 5 / 9;
System.out.println(Double.toString(fahrenheit) + "° Fahrenheit is " + celsius + "° Celsius");
}
}
Output
[edit | edit source]Enter Fahrenheit temperature: 100 100° Fahrenheit is 37.7777777777778° Celsius
Discussion
[edit | edit source]Each new code element represents:
private static Scanner input ...
defines an object to read from standard inputinput.nextDouble()
reads input as a double floating-point value