Transcript Metode di Java

Metode di Java
Risanuri Hidayat, Ir., M.Sc.
Pendahuluan
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Classes usually consist of two things:
• instance variables and
• methods.
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The topic of methods is a large one
because Java gives them so much
power and flexibility.
general form
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This is the general form of a method:
type name(parameter-list) {
// body of method
return value;
}
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type specifies the type of data returned by the method. If the
method does not return a value, its return type must be void.
The name of the method is specified by name.
The parameter-list is a sequence of type and identifier pairs
separated by commas.
Parameters are essentially variables that receive the value of
the arguments passed to the method when it is called.
value is the value returned.
Example
// This program includes a method (Metode.java)
class Metode {
static void volume(double x, double y, double z) {
System.out.println(x*y*z);
}
public static void main(String args[]) {
double vol;
double width = 10;
double height = 20;
double depth = 15;
System.out.print("Volume is ");
volume(width, height, depth);
}
}
Example 2: Returning value
// This program includes a method (Metode1.java)
class Metode1 {
static double volume(double x, double y, double z) {
double v;
v =x*y*z;
return v;
}
public static void main(String args[]) {
double vol;
double width = 10;
double height = 20;
double depth = 15;
vol = volume(width, height, depth);
System.out.print("Volume is ");
System.out.println(vol);
}
}
Example 2: Returning value
// This program includes a method (Metode2.java)
class Metode2 {
static double volume(double x, double y, double z) {
return x*y*z;
}
public static void main(String args[]) {
double vol;
double width = 10;
double height = 20;
double depth = 15;
System.out.print("Volume is ");
System.out.println(volume(width, height, depth));
}
}
Method overloading
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In Java it is possible to define two or more methods within
the same class that share the same name, as long as their
parameter declarations are different.
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When this is the case, the methods are said to be overloaded,
and the process is referred to as method overloading.
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When an overloaded method is invoked, Java uses the type
and/or number of arguments as its guide to determine which
version of the overloaded method to actually call.
Example : Overloading
// Demonstrate method overloading (Overload01.java).
class Overload01 {
static void test() {
System.out.println("No parameters");
} // Overload test for one integer parameter.
static void test(int a) {
System.out.println("a: " + a);
} // Overload test for two integer parameters.
static void test(int a, int b) {
System.out.println("a and b: " + a + " " + b);
} // overload test for a double parameter
Example : Overloading
static double test(double a) {
System.out.println("double a: " + a);
return a*a;
}
public static void main(String args[]) {
double result;
// call all versions of test()
test();
test(10);
test(10, 20);
result = test(123.2);
System.out.println("Result of test(123.2): " + result);
} //main
} // class
Type Conversion
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When an overloaded method is called, Java looks
for a match between the arguments used to call
the method and the method's parameters.
However, this match need not always be exact. In
some cases Java's automatic type conversions
can play a role in overload resolution.
Type Conversion
// Demonstrate method overloading (Overload01.java).
class Overload02 {
static void test() {
System.out.println("No parameters");
}
static void test(int a, int b) {
System.out.println("a and b: " + a + " " + b);
}
Type Conversion
static void test(double a) {
System.out.println("double a: " + a*a);
}
public static void main(String args[]) {
int x=10;
test();
test(10, 20);
test(x);
test(123.5);
}
}
recursion
Java supports recursion. Recursion is
the process of defining something in
terms of itself.
 recursion is the attribute that allows a
method to call itself.
 A method that calls itself is said to be
recursive.
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Example: Recursion
// Demo recursion (Recursion01.java)
class Recursion01 {
static int fact(int n) {
int result;
if(n==1)
return 1;
result = fact(n-1) * n;
return result;
}
Example : Recursion
public static void main(String args[]) {
System.out.println("Factorial of 3 is " + fact(3));
System.out.println("Factorial of 4 is " + fact(4));
System.out.println("Factorial of 5 is " + fact(5));
} //main
} // class
PR
Kerjakan semua contoh di atas
 Kerjakan juga untuk C
 Dikumpulkan minggu depan
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