An array of C+

An array of C+

Declare the array

To declare an array in C+, you need to specify the type of element and the number of elements, as follows:

type arrayName [ arraySize ];

This is called a one-dimensional array. must be an integer constant greater than zero, and type can be any valid type of C+ data. For example, to declare an array of 10 elements of double type double, declare the following statement:

double balance[10];

Balance is now an available array that can hold 10 numbers of double type.

Initialize the array

You can initialize the array one by one in C+, or you can use an initialization statement, as follows:

double balance[5] = {1000.0, 2.0, 3.4, 17.0, 50.0};

The number of values between braces cannot be greater than the number of elements we specify in square brackets when declaring an array.

If you omit the size of the array, the size of the array is the number of elements at the time of initialization. Therefore, if:

double balance[] = {1000.0, 2.0, 3.4, 17.0, 50.0};

You will create an array that is exactly the same as the one created in the previous instance. Here's an example of assigning a value to an element in an array:

balance[4] = 50.0;

The statement above assigns the value of the fifth element in the array to 50.0. A ll arrays are indexed with 0 as their first element, also known as the base index, and the last index of the array is the total size of the array minus 1. The following is a graphical view of the array discussed above:

Access array elements

Array elements can be accessed by indexing the array name. T he index of the element is placed in square brackets, behind the array name. For example:

double salary = balance[9];

The statement above assigns the value of the 10th element in the array to the salary variable. The following example uses the three concepts above, namely, declaring arrays, array assignments, accessing arrays:

#include <iostream>
using namespace std;
 
#include <iomanip>
using std::setw;
 
int main ()
{
   int n[ 10 ]; // n 是一个包含 10 个整数的数组
 
   // 初始化数组元素          
   for ( int i = 0; i < 10; i++ )
   {
      n[ i ] = i + 100; // 设置元素 i 为 i + 100
   }
   cout << "Element" << setw( 13 ) << "Value" << endl;
 
   // 输出数组中每个元素的值                     
   for ( int j = 0; j < 10; j++ )
   {
      cout << setw( 7 )<< j << setw( 13 ) << n[ j ] << endl;
   }
 
   return 0;
}

The above program uses the setw() function to format the output. When the above code is compiled and executed, it produces the following results:

Element        Value
      0          100
      1          101
      2          102
      3          103
      4          104
      5          105
      6          106
      7          107
      8          108
      9          109

The array in C+ is detailed

Arrays are very important in C++ and we need to know more about arrays. Here are some important concepts related to arrays that programmers must be aware of: