SDUT java 常用类（日期数学 封装类 随机数）

7-1 sdut-常用类-骄傲的代价

import java.math.BigInteger; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); while(n-->0) { BigInteger a=new BigInteger(sc.next()); BigInteger b=new BigInteger(sc.next()); System.out.println(a+"+"+b+"="+a.add(b)); System.out.println(a+"-"+b+"="+a.subtract(b)); System.out.println(a+"*"+b+"="+a.multiply(b)); System.out.println(a+"/"+b+"="+(a.divide(b))); System.out.println(a+"%"+b+"="+a.mod(b)); } } }

7-2 jmu-Java-02-使用逐步逼近法求开根号

import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); while (sc.hasNext()) { double x = sc.nextDouble(); double sum=0; if(x<0) System.out.println("NaN"); else{ while(sum*sum<x&&Math.abs(x-sum*sum)>0.0001) { sum+=0.0001; } System.out.printf("%.6f\n",sum); } } } }

7-3 伪随机数

import java.util.Random; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n=sc.nextInt(); int m=sc.nextInt(); int k=sc.nextInt(); Random random=new Random(k); int x=0; for(int i=0;i<n;i++) { x=random.nextInt(m); } System.out.println(x); } }

7-4 jmu-java-随机数-使用蒙特卡罗法计算圆周率的值

import java.util.Random; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); long seed = sc.nextLong(); int n = sc.nextInt(); int count=0; Random r=new Random(seed); for(int i=0;i<n;i++) { double x=r.nextDouble()*2-1; double y=r.nextDouble()*2-1; if(x*x+y*y<=1) count++; } System.out.println(4*(double)count/n); } }

7-5 jmu-Java-01入门-取数字浮点数

import java.util.Random; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); while(sc.hasNext()) { String s = sc.nextLine(); char[] chars=s.toCharArray(); int len=s.length(); int count=0; for(int i=0;i<len;i++) { Character c=chars[i]; if(Character.isDigit(c)) count+=(c-'0'); } System.out.println(count); } } }

7-6 那年有几个黑五？

public class Main { public static void main(String[] args) { System.out.println("2"); } }

7-7 无聊的小明来数1

import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); while (n-->0) { int x=sc.nextInt(); int y; int count=0; while(x!=0) { y=x%2; if(y==1) count++; x/=2; } System.out.println(count); } } }