java第七次作业

1．编写一个简单程序，要求数组长度为5，静态赋值10，20，30，40，50，在控制台输出该数组的值

 

package NineDay;

public class Test1 {
	public static void main(String[] args) {
		int [] arr = {10,20,30,40,50};
		for (int i = 0; i < arr.length; i++) {
			System.out.println(arr[i]);
		}
	}
}

 

　　

2.编写一个简单程序，要求数组长度为5，动态赋值，并在控制台输出该数组的值。

package NineDay;

import java.util.Scanner;

public class Test2 {
	public static void main(String[] args) {
		System.out.println("输入五个数");
		Scanner sc = new Scanner(System.in);
		int [] arr = new int[5];
		for (int i = 0; i < arr.length; i++) {
			arr[i] = sc.nextInt();
		}
		for (int i = 0; i < arr.length; i++) {
			System.out.println(arr[i]);
		}
	}
}

 

　　

3．定义字符型数组，分别存储c、h、 i、n、a 并在控制台输出

package NineDay;

public class Test3 {
	public static void main(String[] args) {
		char [] crr = {'c','h','i','n','a'};
		for (int i = 0; i < crr.length; i++) {
			System.out.print(crr[i]);
		}
	}
}

　　

4．输入5个学生成绩，求总分和平均分

 

package NineDay;

import java.util.Scanner;

public class Test4 {
	public static void main(String[] args) {
		System.out.println("输入学生成绩");
		Scanner sc = new Scanner(System.in);
		double [] arr = new double[5];
		double sum = 0;
		double avg = 0;
		for (int i = 0; i < arr.length; i++) {
			arr[i] = sc.nextInt();
			sum += arr[i];
		}
		avg = sum/arr.length;
		System.out.println("总分是："+ sum +"  "+"平均分是："+avg);
	
	}
}

 

　　

5．定义数组{12,53,23,44,53} 用for和foreach分别输出，再倒序输出(for)

 

package NineDay;

public class Test5 {
	public static void main(String[] args) {
		int [] arr = {12,53,23,44,53};
		System.out.println("for遍历");
		for (int i = 0; i < arr.length; i++) {
			System.out.print(arr[i]+" ");
		}
		System.out.println();
		System.out.println("foreach遍历");
		for (int i : arr) {
			System.out.print(i+" ");
		}
		System.out.println();
		System.out.println("for倒序");
		for (int i = 4; i >= 0; i--) {
			System.out.print(arr[i]+" ");
		}
	}
}

 

　　

作业

1.定义一个整型数组，赋值后求出奇数个数和偶数个数

package NineDay;

public class Test6 {
	public static void main(String[] args) {
		int [] arr ={22,33,44,55,66,77,88,99,10,8};
		int ou =0;
		int ji =0;
		for (int i = 0; i < arr.length; i++) {
			if(arr[i]%2==0){
				ou++;
			}else{
				ji++;
			}
		}
		System.out.println("偶数个数："+ou+ " "+"奇数个数："+ji);
	}
}

　　

2.生成一个100长度数组，里面的数分别是1-100，并输出

package NineDay;

public class Test7 {
	public static void main(String[] args) {
		int [] arr = new int[100];
		for (int i = 0; i < arr.length; i++) {
			arr[i]=i+1;
		}
		for (int i = 0; i < arr.length; i++) {
			System.out.println(arr[i]);
		}
	}
}

　　

3.定义一个double数组，存放10个学生的成绩，给所有同学加5分，不能超过100分。

package homework;

import java.util.Scanner;

public class tets20 {
	public static void main(String[] args) {
		System.out.print("输入学生成绩");
		double[] drr = new double[10];
		Scanner sc = new Scanner(System.in);
		for (int i = 0; i < drr.length; i++) {
			drr[i] = sc.nextDouble();
		}
		for (int i = 0; i < drr.length; i++) {
			if (drr[i] < 100 && drr[i] + 5 > 100) {
				drr[i] = 100;
				System.out.print(drr[i] + " ");
			} else if (drr[i] < 100 && drr[i] + 5 < 100) {
				drr[i] = drr[i] + 5;
				System.out.print(drr[i] + " ");
			}

		}
	}
}