04747_java language Programming (i) _ 4th _ Arrays and strings

Example 4.1 A small application declares an array a, creates it in Method init (), specifies 5 elements, and assigns a value to the array element one after the other. Outputs the values of the elements of the array in the method paint ().

Import Java.applet.*;import java.awt.*;p ublic class Example4_1 extends Applet{int a[];//identifier UA can reference an array of element types that are int public void Init () {A=new int[5];//creates an array with 5 elements and lets a refer to it a[0]=100;a[1]=101;a[2]=102;a[3]=103;a[4]=104;} public void Paint (Graphics g) {g.drawstring ("a[0]=" +a[0]+ "a[1]=" +a[1]+ "a[2]=" +a[2],12,12); g.DrawString ("a[3]=" +a[3 ]+ "a[4]=" +a[4],12,32);}}

Example 4.2 set up an array is a reference type of application.

public class Example4_2{static public void Main (string[] args) {int firstarray[]={1,2,3,4};//creates an array of int with array initialization Secondarray []={5,6,7,8,9,10};int myarray[];//Declaration identifier MyArray can reference an array myarray=firstarray;//myarray like Firstarray, Reference the same array System.out.println ("First array:"); for (int index=0;index<myarray.length;index++) {System.out.println ( Myarray[index]);//by MyArray An array of operations}myarray=secondarray;//let MyArray refer to the other arrays System.out.println ("Second array:"); for ( int index=0;index<myarray.length;index++) {System.out.println (Myarray[index]);//operation by MyArray Array}}}

Example 4.3 an application with a triangular two-dimensional array.

public class Example4_3{static public void Main (string[] args) {Boolean btbl[][]=new boolean[4][];//only describes the first dimension, there are 4 sub-arrays for ( int i=0;i<btbl.length;i++)//Create second dimension {btbl[i]=new boolean[i+1];} for (int i=0;i<btbl.length;i++)//Print group contents {for (int k=0;k<btbl[i].length;k++) {System.out.print (btbl[i][k]+ ") on the screen ");} System.out.println ("");}}

Example 4.4 An application that illustrates string connection operations and connection methods.

public class Example4_4{static public void Main (string[] args) {String s1= "ABC"; String s2= "DEFG"; System.out.println (S1+S2);//Apply String connection operation s1= "ABC"; s2= "XYZ"; s1=s1.concat (s2);//Apply string connection method System.out.println (S1);}}

Example 4.5 An application that describes the character substitution of a string and removes whitespace before and after a string.

public class Example4_5{static public void Main (string[] args) {String s= "1234567788", Str;str=s.replace (' 7 ', ' A '); System.out.println ("s=" +s+ "str=" +str); String s2= "123456", Str2;str2=s2.trim (); System.out.println ("s2=" +s2+ "| str2=" +str2+ "|");}}

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04747_java language Programming (i) _ 4th _ Arrays and strings