Chapter 2 Process Control (for personal use)

Given a one-hundred-point system score, it is required to output five grades of grades'A','B','C','D', and'E'.

（if~else）

import java.util.Scanner;
public class test2 {
	public static void main(String[] args) {
		Scanner input =new Scanner(System.in);
		System.out.println("进入成绩查询系统");
		System.out.println("输入成绩：\n");
		int i=input.nextInt();
		if(i>=90){
			  System.out.println("成绩等级为A");
			 }
		else if((i>=80)&&(i<90)) {
			System.out.println("成绩等级为B");
		}
		else if((i>=70)&&(i<80)) {
			System.out.println("成绩等级为C");
		}
		else if((i>=60)&&(i<70)) {
			System.out.println("成绩等级为E");
		}
		else{
			System.out.println("成绩等级为F");
		}
		
		 }
}

 

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The writing function requires the output of the percentile system score segment according to the grade of the test score. A grade is 85 points or more, B grade is 70 to 84 points, C grade is 60 to 69 points, and D grade is 60 points or less. The grade of achievement is input by keyboard.

(switch)

import java.util.Scanner;
public class Csj02 {
	public static void main(String[] args) {
		Scanner ra = new Scanner(System.in);
		System.out.println("请输入成绩的等级：");
		char rank = ra.next().charAt(0);
		switch (rank) {
		case 'a':
		case 'A':
			System.out.println("成绩为85分以上");             // String a="a";字符串 char b='b';字符 String c="a"+'b';自动向上转型
			break;		case 'b':
		case 'B':
			System.out.println("成绩为70~84分");
			break;
		case 'c':
		case 'C':
			System.out.println("成绩为60~69分");
			break;
		case 'd':
		case 'D':
			System.out.println("成绩为60分以下");
			break;
		default:
			System.out.println("输入的成绩等级错误");
		}
	}
}

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Write a program to output the first 20 numbers in the Fibonacci sequence

(For loop structure)

 
public class Work8 {
 
	public static void main(String[] args) {
		// TODO Auto-generated method stub
 
		//裴波那契数列
		System.out.println("裴波那契数列的前20位数是:");
		System.out.print("1\t1\t");
		int first = 1;
		int second = 1;
		int next=0;
		
		for (int i = 3; i < 21; i++) {
			next = first+second;
			first = second;
			second = next;
			System.out.print(next+"\t");
			
			if(i%5==0){
				System.out.println("");//默认加一个换行符
			}
		}
	}
}