double 0.0 char \u0000,stay window The system parses spaces String null boolean false
4.10: once the array has allocated space, it can be used
4.11: array direct output, the output is the memory address
5.2D array usage
5.1: syntax of two-dimensional array declaration: data type [] [] array name; (recommended)
Data type array name[][]; eg://Declare a two-dimensional array String[][] stuName1; int stuAges1[][];
5.2: two dimensional array allocation space
5.2.1:Allocate space to a declared two-dimensional array:Fixed length of two-dimensional array,The length of each one-dimensional array is variable. Array name=new data type[Length of two-dimensional array][] Array name[Two dimensional array index]=new data type[Length of one-dimensional array]; 5.2.2:Allocate space to a declared two-dimensional array:The length of each element of a two-dimensional array, that is, a one-dimensional array, is also fixed. Array name=new data type[Length of two-dimensional array][Length of one-dimensional array]; 5.2.3:Allocate space while declaring a two-dimensional array: data type[][] Array name=new data type[Length of two-dimensional array][] Array name[Two dimensional array index]=new data type[Length of one-dimensional array]; 5.2.4:Allocate space while declaring a two-dimensional array: data type[][] Array name=new data type[Length of two-dimensional array][Length of one-dimensional array]; eg://First: allocate space to the array stuName1=new String[3][4]; //Second: allocate space to the array stuAges1=new int[3][]; stuAges1[0]=new int[2]; stuAges1[1]=new int[4]; stuAges1[2]=new int[3]; //The third is to declare the array and allocate space at the same time double[][] height1=new double[3][2]; //The fourth is to declare the array and allocate space at the same time. The length of one-dimensional array is uncertain double[][] weight1=new double[2][]; weight1[0]=new double[3]; weight1[1]=new double[2];
5.3: 2D array assignment
5.3.1:Dynamic assignment:It can be used in any case. Array name[Two dimensional array index][One dimensional array index]=value; eg://Dynamic assignment to two-dimensional array stuName1[0][0]="Zhang San 1"; stuName1[0][1]="Zhang San 2"; stuName1[0][2]="Zhang San 3"; stuName1[0][3]="Zhang San 4"; stuName1[1][0]="Li Si 1"; stuName1[1][1]="Li Si 2"; stuName1[1][2]="Li Si 3"; stuName1[1][3]="Li Si 4"; 5.3.2:Static assignment:Used when array elements are known 5.3.2.1:Array will be declared,Allocate space to an array,Static assignment three in one syntax: data type[][] Array name=new data type[][]{{Value 10,Value 11...},{Value 20,Value 21...}...}; 5.3.2.2:Array will be declared,Allocate space to an array,Static assignment three in one syntax: data type[][] Array name={{Value 10,Value 11...},{Value 20,Value 21...}...}; eg://Static assignment to array int[][] stuAges2=new int[][] {{20,30},{23,24,25}}; //Static assignment to array double[][] height2= {{1.75,1.8},{1.7,1.72},{1.6,1.69}};
5.4: two dimensional array traversal
eg:/*Traversing a two-dimensional array with a for loop*/ //The outer loop traverses each space of a two-dimensional array for (int i = 0; i < stuName1.length; i++) { //The inner loop traverses each element of the two-dimensional array, that is, each space of the one-dimensional array for (int j = 0; j < stuName1[i].length; j++) { System.out.print(stuName1[i][j]+"\t"); } //Output two-dimensional array and wrap one-dimensional array in each space System.out.println(); } System.out.println("*****************************************"); /*Traversing a two-dimensional array with an enhanced for loop*/ //The outer loop traverses each space of a two-dimensional array for (double[] ds : height2) { //The inner loop traverses each element of the two-dimensional array, that is, each space of the one-dimensional array for (double d : ds) { System.out.print(d+"\t"); } //Output two-dimensional array and wrap one-dimensional array in each space System.out.println();
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Video of working overtime for two weeks to 2 a.m. If you want to get a high salary in this industry, you have no choice but to improve your hard power.
You know what? Now some fresh students' internship salary has surpassed that of programmers who have been developing for 5 years. The internship salary is 26K and 30K. Don't you have a sense of urgency? It's really embarrassing to be a fresh student after so many years!
If you enter this industry, don't use the lack of time to learn as an excuse. This industry is to keep learning, otherwise you can only be laid off. Therefore, seize the time to invest in yourself, learn more technology, face difficulties and relax in the future!
To get these carefully sorted out materials, please remember
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