Java Sample Collection (iv)

Example 1. The transpose operation of the moment Chen

The so-called Torque Chen's transpose is the moment of the ranks of the interchange. The sample code is as follows:

 Public classArrayrowcolumnswap { Public Static voidMain (string[] args) {//TODO auto-generated Method Stub        intarr[][]=New int[][]{{10,11,12},{20,21,22},{30,31,32}};//creating a two-dimensional arraySYSTEM.OUT.PRINTLN ("****** before the transfer of the moment Chen is: ******");        PrintArray (arr); //output two-dimensional arrays        intarr2[][]=New int[Arr.length][arr.length];  for(inti=0; i<arr.length;i++) {//adjust array row and column data             for(intj=0;j<arr[i].length;j++) {Arr2[j][i]=Arr[i][j]; }} System.out.println ("****** after the transfer of the moment Chen is: ******");    PrintArray (ARR2); }     Public Static voidPrintArray (int[] arr) {         for(inti=0;i<arr.length;i++) {//iterating through an array             for(intj=0;j<arr.length;j++) {System.out.print (Arr[i][j]+ "\ T");        } System.out.println (); }    }}

The results of its implementation are as follows:

The moment before the transpose is: ******10 each of the    ******,    The moment Chen is: ******10    32 off    

Example 2. The trace of Fang Chen
Fangchen traces, i.e. the Fangchen of all elements on the main diagonal. The sample code is as follows:

 Public classTrace { Public Static voidMain (string[] args) {//TODO auto-generated Method Stub        intarr[][]= {//creating a two-dimensional array{5,10,15,20},                {10,15,20,25},                {15,20,25,30},                {20,25,30,35}        }; intTr=0; System.out.println ("******** Fangchen arr[][] Yes: ********");  for(inti=0;i<arr.length;i++) {//iterating through an array             for(intj=0;j<arr[i].length;j++) {System.out.print (Arr[i][j]+ "\ T");        } System.out.println (); }         for(inti=0;i<arr.length;i++) {TR+=Arr[i][i]; } System.out.println ("Fang Chen arr[][" The trace is: "+tr); }}

The execution results are:

Fangchen arr[][] is: ********5-ten    30        The traces of Fangchen arr[][] are:80

Example 3. Iterating through an array
3.1. Traverse a

 Public classGetDay { Public Static voidMain (string[] args) {//TODO auto-generated Method Stub        intday[]= {31,28,31,30,31,30,31,31,30,31,30,31};//Create and initialize a one-dimensional array         for(inti=0;i<day.length;i++) {//using fou loops to output informationSystem.out.print ((i+1) + "month has" +day[i]+ "Day" + "\t\t"); if((i+1)%3==0) {//If the sum of i+1 is zeroSystem.out.print ("\ n");//Output Enter            }        }    }}

The execution results are shown below:

January There are 31 days in        February there are 28 days        March There are 31 days        April There are 30 days        May has 31 days        June has 30 days        July has 31 days        August has 31 days        September has 30 days        October There are 31 days in        November there are 30 days        December there are 31 days    

3.2. Iterate through the two-dimensional array, the sample code is as follows:

 Public classTrap { Public Static voidMain (string[] args) {//TODO auto-generated Method StubSYSTEM.OUT.PRINTLN ("* * * * * * * * * use for loop traversal of two-dimensional arrays"); intarr[][]=New int[][] {            {10,20},            {12,13,14,15,16},            {17,18,19}        }; //creating a two-dimensional array         for(inti=0;i<arr.length;i++) {             for(intj=0;j<arr[i].length;j++) {//iterate through each element in a two-dimensional arraySystem.out.print (arr[i][j]+ "");        } System.out.println (); } System.out.println (* * * * * * Use foreach statement to traverse a two-dimensional array * * * *);  for(int[] X:arr) {//the outer loop variable is a one-dimensional array             for(intY:X) {//iterate through each array elementSystem.out.print (y+ "");        } System.out.println (); }    }}

The result of the execution is:

　　

Java Sample Collection (iv)