求圆的周长、面积

import java.util.Scanner;
public class TestCircle {
	
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		Circle c = new Circle();
		System.out.print("请输入圆半径：");
		c.radius = s.nextDouble();
		System.out.println("圆半径为："+c.getRadius());
		System.out.println("圆周长为："+c.findGirth());
		System.out.println("圆面积为："+c.findArea());
	}

}

class Circle{
	double radius;//半径
	
	public double findGirth() {//计算周长
		return 3.14*radius*2;
	}
	
	public double findArea() {//计算面积
		return 3.14*radius*radius;
	}

	public double getRadius() {
		return radius;
	}

	public void setRadius(double radius) {
		this.radius = radius;
	}
	
}

现在已知数组int[] arr = {12,34,465,3,45}; 将最大值和最小值的位置进行交换

/*
 * 现在已知数组int[] arr = {12,34,465,3,45};
 * 将最大值和最小值的位置进行交换
 */
public class Test {
 
	public static void main(String[] args) {
		int[] arr = {12,34,456,3,45};
		
		System.out.print("arr[]:");
		for(int i = 0; i<arr.length; i++) {
			System.out.print(arr[i]+" ");
		}
		System.out.println();
		
		//max,min
		int maxIndex = 0;
		int minIndex = 0;
		for(int i = 1; i<arr.length; i++) {
			if(arr[maxIndex] < arr[i]) {
				maxIndex = i;
			}
			if(arr[minIndex] > arr[i]) {
				minIndex = i;
			}
		}
		System.out.println("maxIndex:"+maxIndex+" "+"minIndex:"+minIndex);
		
		int a = arr[maxIndex];
		arr[maxIndex] = arr[minIndex];
		arr[minIndex] = a;
		
		//
		System.out.print("交换后arr[]:");
		for(int i = 0; i<arr.length; i++) {
			System.out.print(arr[i]+" ");
		}
		System.out.println();
 
	}
 
}

运行结果

arr[]:12 34 456 3 45 
maxIndex:2 minIndex:3
交换后arr[]:12 34 3 456 45