C++ 中的数组类
C++ 中的数组类足够高效,并且知道其自身的大小。
用于对数组执行操作的函数为
- size() = 返回数组的大小,即返回数组的元素数。
- max_size() = 返回数组的最大元素数。
- get()、at()、运算符 [] = 访问数组元素。
- front() = 返回数组的第一个元素。
- back() = 返回数组的最后一个元素。
- empty() = 如果数组大小为 true,则返回 true,否则返回 false。
- fill() = 用特定值填充整个数组。
- swap() = 交换一个数组与另一个数组的元素。
这里有一个示例来实现上述所有操作 −
示例代码
#include<iostream> #include<array> using namespace std; int main() { array<int,4>a = {10, 20, 30, 40}; array<int,4>a1 = {50, 60, 70, 90}; cout << "The size of array is : "; //size of the array using size() cout << a.size() << endl; //maximum no of elements of the array cout << "Maximum elements array can hold is : "; cout << a.max_size() << endl; // Printing array elements using at() cout << "The array elements are (using at()) : "; for ( int i=0; i<4; i++) cout << a.at(i) << " "; cout << endl; // Printing array elements using get() cout << "The array elements are (using get()) : "; cout << get<0>(a) << " " << get<1>(a) << " "<<endl; cout << "The array elements are (using operator[]) : "; for ( int i=0; i<4; i++) cout << a[i] << " "; cout << endl; // Printing first element of array cout << "First element of array is : "; cout << a.front() << endl; // Printing last element of array cout << "Last element of array is : "; cout << a.back() << endl; cout << "The second array elements before swapping are : "; for (int i=0; i<4; i++) cout << a1[i] << " "; cout << endl; // Swapping a1 values with a a.swap(a1); // Printing 1st and 2nd array after swapping cout << "The first array elements after swapping are : "; for (int i=0; i<4; i++) cout << a[i] << " "; cout << endl; cout << "The second array elements after swapping are : "; for (int i = 0; i<4; i++) cout << a1[i] << " "; cout << endl; // Checking if it is empty a1.empty()? cout << "Array is empty": cout << "Array is not empty"; cout << endl; // Filling array with 1 a.fill(1); // Displaying array after filling cout << "Array content after filling operation is : "; for ( int i = 0; i<4; i++) cout << a[i] << " "; return 0; }
输出
The size of array is : 4 Maximum elements array can hold is : 4 The array elements are (using at()) : 10 20 30 40 The array elements are (using get()) : 10 20 The array elements are (using operator[]) : 10 20 30 40 First element of array is : 10 Last element of array is : 40 The second array elements before swapping are : 50 60 70 90 The first array elements after swapping are : 50 60 70 90 The second array elements after swapping are : 10 20 30 40 Array is not empty Array content after filling operation is : 1 1 1 1
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