本文共 4062 字，大约阅读时间需要 13 分钟。

1.计算出8/5的值保留小数点1位。

class calculate{	public static void main(String[] args){		double result = 8.6/5.0;		ps("%.1f",result);	}		public  static 
   
     void p(T t){		System.out.println("result:"+t);	}		public  static 
    
      void ps(String s,T t){		System.out.printf(s,t);	}}
    
   

2.复杂的表达式计算

class calculate{	public static void main(String[] args){		double result = 1+2*Math.sqrt(3)/(5-0.1);		ps("%.8f",result);	}		public  static 
   
     void p(T t){		System.out.println("result:"+t);	}		public  static 
    
      void ps(String s,T t){		System.out.printf(s,t);	}}
    
   

3.计算圆柱体表面积，输出圆柱体表面积，保留3位小数

 样例输入：3.5   9

样例输出：Area = 274.889

过程：

double jishuPI(double z){          double sum=2;          int n=1;          int m=3;          double t=2;          while(t>z){              t=t*n/m;              sum=sum+t;              n++;              m+=2;          }          return sum;      }

java程序：

import java.util.Scanner;class calculate{	public static void main(String[] args){		Scanner sc = new Scanner(System.in);		s("please input a r and a h to get area");		double r = sc.nextFloat();		double h = sc.nextFloat();		double pi = jishuPI(1e-15);		double result = 2*pi*r*r + 2*pi*r*h;		ps("Area = %.3f",result);	}		public  static 
   
     void p(T t){		System.out.println("result:"+t);	}		public static void s(String s){		System.out.println(s);	}		public  static 
    
      void ps(String s,T t){		System.out.printf(s,t);	}		public static double jishuPI(double z){          double sum=2;          int n=1;          int m=3;          double t=2;          while(t>z){              t=t*n/m;              sum=sum+t;              n++;              m+=2;          }          return sum;      }  }
    
   

顺序结构程序设计

4.三位数反转，输入一个数，分离出它的百位、十位、个位，反转后输出

样例输入：127

样例输出：721

import java.util.Scanner;class calculate{	public static void main(String[] args){		Scanner sc = new Scanner(System.in);		int r = sc.nextInt();		int bai = r/100;		int shi = (r/10%10) * 10;		int ge = (r%10) * 100;		if(ge == 0){			ps("Area = %s","0"+(shi+bai));		}else{			ps("Area = %d",ge+shi+bai);		}					}	public  static 
   
     void ps(String s,T t){		System.out.printf(s,t);	}}
   

5.变量转换，输入两个整数a和b，交换二者值，然后输出

样例输入：824 16

样例输出：16 824

方法一：

import java.util.Scanner;class calculate{	public static void main(String[] args){		Scanner sc = new Scanner(System.in);		int a = sc.nextInt();		int b = sc.nextInt();		int c = a;		a = b;		b = c;		ps("%d %d",a,b);	}	public  static 
   
     void ps(String s,T t,T r){		System.out.printf(s,t,r);	}}
   

方法二：

import java.util.Scanner;class calculate{	public static void main(String[] args){		Scanner sc = new Scanner(System.in);		int a = sc.nextInt();		int b = sc.nextInt();		a += b;		b = a - b;		a = a - b;		ps("%d %d",a,b);	}	public  static 
   
     void ps(String s,T t,T r){		System.out.printf(s,t,r);	}}
   

方法三：

import java.util.Scanner;class calculate{	public static void main(String[] args){		Scanner sc = new Scanner(System.in);		int a = sc.nextInt();		int b = sc.nextInt();		ps("%d %d",b,a);	}	public  static 
   
     void ps(String s,T t,T r){		System.out.printf(s,t,r);	}}
   

分支结构设计

已知鸡和兔的总数为n，总腿数为m，输入n和m，依次输出鸡和兔的数目，如果无解，则输出“No Answer”

样例输入：14 32

样例输出：12 2

样例输入：10 16

样例输出：No Answer

import java.util.Scanner;class calculate{	public static void main(String[] args){		Scanner sc = new Scanner(System.in);		int n = sc.nextInt();		int m = sc.nextInt();		int y = (m - 2*n)/2;		int x = (4*n - m)/2;		int nImpl = x + y;		int mImpl = 2*x + 4*y;		if(nImpl == n && mImpl == m && x >= 0 && y >= 0){			ps("%d %d",x,y);		}else{			System.out.printf("No Answer");		}			}	public  static 
   
     void ps(String s,T t,T r){		System.out.printf(s,t,r);	}}
   

三整数排序

输入3个整数，从小到大排序后输出

输入样例：20 7 33

输出样例：7 20 33

import java.util.Scanner;class calculate{	public static void main(String[] args){		Scanner sc = new Scanner(System.in);		int[] a = new int[3];		a[0] = sc.nextInt();		a[1] = sc.nextInt();		a[2] = sc.nextInt();		//冒泡排序		for(int i = 0;i < a.length - 1;i++){			if(a[i] > a[i+1]){				int t = a[i];				a[i] = a[i+1];				a[i+1] = t;			}		}		System.out.printf("%d %d %d",a[0],a[1],a[2]);	}}