Learn Java syntax from the topic

I. INPUT and OUTPUT

1. Enter the radius of the circle to calculate and output the circumference and area of the circle:

ImportJava.util.Scanner; Public classzuoye01_circle { Public Static voidMain (string[] args) {Scanner sc=NewScanner (system.in); Instantiate input System.out.print ("Please enter the radius of the circle:"); DoubleR=sc.nextdouble (); Receives the input value and assigns a value to rDoubleZhouchang = 2*math.pi*0; DoubleMianji = Math.pi*math.pow (R, 2); System.out.println (The circumference of a circle with a radius of +r+ is: "+Zhouchang); System.out.println (The area of the circle with radius "+r+" is: "+Mianji); }}

Second, if statement

2, console input age, according to age output different tips

ImportJava.util.Scanner; Public classZuoye02_nianlingpanduan { Public Static voidMain (string[] args) { for(inti=0;i<1;i++) {Scanner sc=NewScanner (system.in); System.out.print ("Please enter your Age:"); intAge =Sc.nextint (); if(Age>0 && age<135){            if(age<18) {System.out.println ("You are underage!" "); }            Else if(age<60) {System.out.println ("You are an adult!" "); }            Else{System.out.println ("You are old!" "); }        }        Else{System.out.println ("You entered the wrong age!" You can only enter numbers from 1 to 135! "); I--; }        }    }}

Third, the circular statement

1, a piece of paper thickness of about 0.08mm, fold how many times can reach the height of Mount Everest (8848.13 meters)?

 Public class Zuoye03_zhedie {    publicstaticvoid  main (string[] args) {          Double Zhi = 0.08;          for (int i =1;i>0;i++) {            zhi*=2;             if (zhi>=8848130) {                System.out.println ("folded" +i+ "times, exceeding the height of Everest");                  Break ;            }        }    }}

2, calculate the factorial of 5 5! What's the result?

public class Zuoye04_jiecheng {
public static void Main (string[] args) {
int S=1;
for (int i=1;i<=5;i++) {
S*=i;
}
System.out.println (The factorial of "5" is: "+s");
}
}

3. Calculation 1+1/2!+1/3!+1/4!+ ... 1/20!=?

 Public classZuoye05_jiechengqiuhe { Public Static voidMain (string[] args) {DoubleSum=0;  for(inti=1;i<=20;i++){            DoubleS=1;  for(intj=1;j<=i;j++) {s*=J; } Sum+ = (1/s); } System.out.println ("The result is:" +sum); }}

4, print out all the "Narcissus number", so-called "Narcissus number" refers to a three-digit number, the number of its members of the cubic and equal to the number itself. For example: 153 is a "narcissus number", because the 153=1 three times the square +5 of the three +3 Times Square.

 Public classZuoye06_shuixianhuashu { Public Static voidMain (string[] args) { for(inti=100;i<=999;i++){            inta=i/100; intb= (i%100)/10; intC= (i%100)%10; if(Math.pow (a,3) +math.pow (b, 3) +math.pow (c,3) = =i)            {System.out.println (i); }        }    }}

6, the ancient Chinese mathematician Zhang Chujian in the "Calculation of the book" in a "hundred money to buy hundred chickens" problem, test instructions is this: 5 Money can buy a rooster, 3 money can buy a hen, 1 money can buy 3 chicks. Now buy 100 chickens with 100 cents, so how many cocks, hens and chicks are there? Please write a program implementation.

 Public classZuoye07_baiqianbaiji { Public Static voidMain (string[] args) {intA,b,c; intI=0;  for(a=0;a<=20;a++){             for(b=0;b<=33;b++){                 for(c=0;c<=100;c++){                    if(C%3==0 && (5*A+3*B+C/3) ==100 && (a+b+c) ==100) {i++; System.out.println ("+i+" type buy Method: "+a+" only Rooster, "+b+" only hen, "+c+" only chick. "); Continue; }                }            }        }    }}

7, this is the classic "Hundred Horse Hundred Bear" problem, there are 100 horses, carry 100, the big horse carries 3, the horse carries 2 to bear, two small horse carries 1, ask has big, medium, pony each several horses?

 Public classZuoye08_baimabaidan { Public Static voidMain (string[] args) {intA,b,c; intI=0;  for(a=0;a<=33;a++){             for(b=0;b<=50;b++){                 for(c=0;c<=100;c++){                    if((a+b+c) ==100 && c%2==0 && (3*a+2*b+c/2==100) ) {i++; System.out.println ("+i+" Camel Law: "+a+" only big horse, "+b+" only in the horse, "+c+" only pony. "); }                }            }        }    }}

8, console output 99 multiplication table

 Public class Zuoye09_chengfabiao {    publicstaticvoid  main (string[] args) {          for (int i=1;i<=9;i++) {            for (int j=1;j<=i;j++) {                System.out.print (J+ "x" +i+ "=" + (i*j) + "\ T");            }            System.out.println ();     }}}

9. Console output Triangles and diamonds

 Public class zuoye10_sanjiaoxing {    publicstaticvoid  main (string[] args) {          for (int i=1;i<=5;i++) {            for (int j=1;j<=i;j++) {                System.out.print ("★" + "");            }            System.out.println ();     }}}

 Public classzuoye11_lingxing { Public Static voidMain (string[] args) { for(inti=0;i<=5;i++){             for(intk=0;k<=5-i;k++) {System.out.print (" "); }             for(intj=0;j<=2*i;j++) {System.out.print ("*");        } System.out.println (); }         for(inti=1;i<=5;i++){             for(intk=1;k<=i+1;k++) {System.out.print (" "); }             for(intj=1;j<=11-2*i;j++) {System.out.print ("*");        } System.out.println (); }    }}

Learn Java syntax from the topic