Arrays are often used for scientific calculation or storage of some variables of the same type

The way to write c

#include <stdio.h>

int main() {
    double array1[2] = {1.0, 2.25};  //The element is an array of type double, and the length of the array specified at the time of definition is 2
    int array2[] = {1,2,3};  //The element is an array of type int, which can be used if you do not know the number of elements when defining
    printf("array2[0]=%d\n", array2[0]);  //Find elements based on their Subscripts

    int array3[2][2] = {
            {1,2},
            {3,4}
    };  //Define a two-dimensional array. If you define a multi-dimensional array, add more brackets
    printf("array[1][1]=%d\n", array3[1][1]);

    int array4[3];  //An array is defined but not initialized
}

The array in c is not added or deleted

The way to write c++

#include <iostream>
#include <string.h>
#Include < vector > / / vector header file needs to be introduced

using namespace std;
int main() {
    //The array definition in c also applies to c++
    int array1[2] = {1,2};
    int array2[] = {1,2};

    //More convenient vector is added in c + +
    vector<int> vector1;  //Declare a vector vector1 of type int
    vector<int> vector2(10);  //Declare a vector vector2 of type int with an initial size of 10
    vector<int> vector3(10,0);  //Declare a vector vector3 of type int with an initial size of 10 and an initial value of 0
    vector3[0] = 15;  //Assign a value to the first element of vector3
    std::cout << vector3[0] << std::endl;  //View the first element of vector3

    vector3.erase(vector3.begin(), vector3.begin()+1);  //Delete element in vector
    std::cout << vector3.size() << std::endl;  //Viewing the length of a vector

    vector3.insert(vector3.begin(),vector3.begin(), vector3.begin()+3);  //Insert all elements between vector3.begin() and vector3.begin()+3 before vector3.begin()
    std::cout << vector3.size() << std::endl;  //Viewing the length of a vector

    vector< vector<int> > vector4(10, vector<int>(5));        //Create a 10 * 5 int type 2D vector
}

java writing

public class ArrayDemo {
    public static void main(String[] args) {
        int[] array1;  //Defines an array of type int, uninitialized
        int[] array2 = {1,2,3};

        array2[0] = 4;  //Change element
        System.out.println(array2[0]);  //Find the first element of an array
    }
}

The way to write go

func arrayDemo() {
   array1 := [5]int{}  //Declared array, not
   array2 := [...]int{1,2,3,4,5}  //Declaration array
   array3 := [2][2]int{{1,2}, {3,4}}  //Declare a 2D array

   println(array1[0])  //Find elements of an array
   println(array2[0])
   println(array3[0][0])
}

The function of slicing in go is similar to list, which will be introduced later. It is not confused with array here

The writing method of python

There is no concept of array in python. If you want to use array, you can directly use list to implement related functions

Comparative summary:

1. In addition to python, arrays can be defined by c, c + +, java and go, and arrays can only be changed and searched, not added and deleted directly.
2. c + + has more function of vector than c, it is convenient to add, delete, search and modify arrays;
3. python has no concept of array;
4. c, c + +, java and go need curly braces to define elements when defining arrays (later chapters will explain how to remember and quickly view the syntax of each language);