A few small programs of Javaapi Lang

/*write a method to count the number of digits, the number of spaces, the number of lowercase English letters, and the number of uppercase letters in a string. */classCensus {String str; intnum; intCHS; intupcase; intlowcase;  Publiccensus () {} PublicCensus (String str) { This();  This. str =str; }     Public intGetChar () {Char[] ch =Str.tochararray ();  for(inti = 0; i < ch.length; i++) {            if(Character.isletter (Ch[i])) {CHS++;                    }; }        returnCHS; }     Public intGetnum () {Char[] ch =Str.tochararray ();  for(inti = 0; i < ch.length; i++) {            Charc =Ch[i]; if(Character.isdigit (Ch[i])) {num++;        }; }        returnnum; }     Public intgetupcase () {Char[] ch =Str.tochararray ();  for(inti = 0; i < ch.length; i++) {            Charc =Ch[i]; if(Character.isuppercase (Ch[i])) {upcase++;        }; }        returnupcase; }     Public intgetlowcase () {Char[] ch =Str.tochararray ();  for(inti = 0; i < ch.length; i++) {            Charc =Ch[i]; if(Character.islowercase (Ch[i])) {Lowcase++;        }; }        returnlowcase; } @Override PublicString toString () {return"str=" + str + ", number of numbers =" + This. Getnum () + ", number of characters =" + This. GetChar ()+ ", number of uppercase letters =" + This. Getupcase () + ", number of lowercase letters =" + This.    Getlowcase (); }            } Public classcensustest{ Public Static voidMain (string[] args) {Census a=NewCensus ("78uijkiiorey228");                System.out.println (A.tostring ()); }}

Calculates the distance between a circle's area and perimeter, and the center point to the origin.

classPoint {//defining the Point class    Doublex; Doubley; DoubleZ;  PublicPoint () {} PublicPoint (DoubleXDoubleYDoublez) { This();  This. x =x;  This. y =y;  This. z =Z; } @Override PublicString toString () {return"Point [x=" + x + ", y=" + y + ", z=" + z + "]"; }     Public DoubleDistanceofo () {returnMATH.SQRT (x*x+y*y+z*z); }} Public classpointtest{ Public Static voidMain (string[] args) {Point a=NewPoint (15,19,23);         System.out.println (A.distanceofo ()); //output Double type point to Origin distanceSystem.out.println (String.Format ("%.2f", (A.distanceofo ())));//output two digits after the decimal digit    }}

classCircleextendspoint{//defines a subclass the circle parent class is a point    Doubleradius;  PublicCircle () {} PublicCircle (DoubleXDoubleYDoubleZDoubleradius) {        Super(x, y, z);  This. Radius =radius; }     Public DoubleGetperimeter () {//Calculate Perimeter        return(math.pi*radius*2); }     Public DoubleGetarea () {return(Math.pi*radius*radius);//Calculate Area    }        } Public classCircletest { Public Static voidMain (string[] args) {Circle a=NewCircle (10,20,32,25); System.out.println (a.tostring ()+ "Circle area of Coordinate point ==>" +A.getarea ()); System.out.println (a.tostring ()+ "Coordinate point circumference length ==>" +A.getperimeter ()); }}

Calculate a large number factorial using one line of code

ImportJava.math.BigInteger;ImportJava.util.Scanner; Public classFactorial { Public StaticBigInteger FAC (intN) {        return(n = = 1?)NewBigInteger ("" + 1):NewBigInteger ("+n"). Multiply (FAC (n-1))); }     Public Static voidMain (string[] args) {Scanner a=NewScanner (system.in); System.out.println ("Please enter a number"); intSCR =A.nextint (); SYSTEM.OUT.PRINTLN (SCR+ "factorial = =" +FAC (SCR)); }}

A few small programs of Javaapi Lang