显示方法嵌套的 Java 程序
原文:https://www . geesforgeks . org/Java-program-to-show-the-nesting-of-methods/
在 java 中，我们在一个类中创建的方法和变量只能用该类的对象来调用，或者在静态方法的情况下，我们可以直接用类名来调用。方法和变量可以在点运算符的帮助下调用。但是有一种特殊情况，一个方法也可以借助类名被另一个方法调用，但条件是它们应该存在于同一个类中。
语法:
class Main
{
method1(){
// statements
}
method2()
{
// statements
// calling method1() from method2()
method1();
}
method3()
{
// statements
// calling of method2() from method3()
method2();
}
}
例 1:
在下面的示例中，该类包含两种方法，即面积()和体积()，后者用于计算球体的面积和体积。main()方法是调用 area()方法计算球体的面积，调用 volume()方法计算球体的体积，然后显示结果。
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program implementing the Nesting of Methods
public class NestingMethodCalls1 {
public void Area(double r)
{
// value of r is coming from main method from which
// this method is called Math.pi is used for getting
// the value of pi
System.out.println(
"****** Inside Area method ******");
// calculate area
double a = 4 * Math.PI * r * r;
// print the area
System.out.println("Surface area of a Sphere is : "
+ a);
}
public void Volume(double r)
{
// value of r is coming from main method from which
// this method is called Math.pi is used for getting
// the value of pi
System.out.println(
"****** Inside Volume method ******");
// calculate the volume
double v = (4 / 3) * Math.PI * r * r * r;
// print the volume
System.out.println("Volume of a Sphere is : " + v);
}
public static void main(String args[])
{
// creating object of class GeeksforGeeks
GeeksforGeeks gfg = new GeeksforGeeks();
// calling of method Area() from main method
gfg.Area(12);
// calling of method Volume() from main method
gfg.Volume(12);
}
}
Output
****** Inside Area method ******
Surface area of a Sphere is : 1809.5573684677208
****** Inside Volume method ******
Volume of a Sphere is : 5428.672105403162
例 2:
在下面的示例中，类包含两个方法，即 swap()和 gfg1()。swap()方法用于交换两个变量，gfg1()方法用于添加两个数字。main()方法调用带有两个值的 gfg1()方法来添加两个数字，gfg1()方法调用 swap()方法来执行两个数字的交换。
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program implementing the Nesting of Methods
public class NestingMethodCalls2 {
public void swap(int x, int y)
{
System.out.println(
"*********This is swap method***********");
System.out.println("Before swapping:x=" + x + " "
+ "y=" + y);
// swap the numbers
int z = x;
x = y;
y = z;
System.out.println("After Swapping:a=" + x + " "
+ "b=" + y);
}
public void gfg1(int a, int b)
{
System.out.println(
"*********This is gfg1 method***********");
System.out.println("Before performing operation:a="
+ a + " "
+ "b=" + b);
a = a + 10;
b = b + 12;
System.out.println("After operation:a=" + a + " "
+ "b=" + b);
// calling of swap() method from gfg1() method
swap(a, b);
}
public static void main(String args[])
{
// creating the object of class GeeksforGeeks2
GeeksforGeeks2 gfg2 = new GeeksforGeeks2();
int a = 20, b = 30;
// calling of method gfg1() from main method
gfg2.gfg1(a, b);
}
}
Output
*********This is gfg1 method***********
Before performing operation:a=20 b=30
After operation:a=30 b=42
*********This is swap method***********
Before swapping:x=30 y=42
After Swapping:a=42 b=30
例 3:
在下面的示例中，类包含三个方法，即 a1()，a2()，a3()。main()方法用值 a 和 b 调用 a3()方法，然后 a2()调用另一个方法 a1()，然后这个方法执行所有操作，然后将它们的值传递给另一个方法，这意味着这个方法然后调用另一个方法，即 a2()，然后这个方法将执行，然后程序终止。
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program implementing the Nesting of Methods
public class NestingMethodCalls3 {
public void a1(int a, int b)
{
a = a + 10;
b = b + 20;
System.out.println(
"****** Inside a1 method ******");
System.out.println("a = " + a + " "
+ "b = " + b);
// calling method a2() from a1() with parameters a
// and b
a2(a, b);
}
public void a2(int x, int y)
{
x = x + 100;
y = y + 200;
System.out.println(
"****** Inside a2 method ******");
System.out.println("x = " + x + " "
+ "y = " + y);
}
public void a3(int w, int z)
{
w = w + 50;
z = z - 50;
System.out.println(
"****** Inside a3 method ******");
System.out.println("w = " + w + " "
+ "z = " + z);
// calling method a1() from method a3() with
// parameters w and z
a1(w, z);
}
public static void main(String[] args)
{
// creating the object of class GeeksforGeeks3()
GeeksforGeeks3 gfg3 = new GeeksforGeeks3();
int a = 100, b = 200;
// calling method a3() from main() method
gfg3.a3(a, b);
}
}
Output
****** Inside a3 method ******
w = 150 z = 150
****** Inside a1 method ******
a = 160 b = 170
****** Inside a2 method ******
x = 260 y = 370
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