C++ Assign an array to another array

C++ Assign an array to another array

Looping traversal assignment

Use a loop structure (such as for loops) to perform assignment copying elements.

Here is the sample code:

#include <iostream>

const int SIZE = 5;  // The size of the array
int main() {
    int arr1[SIZE] = {1, 2, 3, 4, 5};  // Original array    int arr2[SIZE];  // Target array
    // Assign the value of arr1 to arr2    for (int i = 0; i < SIZE; ++i) {
        arr2[i] = arr1[i];
    }

    // Print the value of arr2    for (int i = 0; i < SIZE; ++i) {
        std::cout << arr2[i] << " ";
    }
    std::cout << std::endl;

    return 0;
}

In the above code, two arrays are definedarr1andarr2and use a loop structure toarr1Assign the values ​​to eacharr2. Then we use another loop to printarr2value.

Run the above code and the output will be:

1 2 3 4 5

This showsarr2Successfully fromarr1The same value was received.

Use the functions std::copy or std::memcpy in the standard library

In C++, use the assignment operator directly=It is possible to implement the address assignment of one array to another array. However, the contents of the array are not copied. This will cause two arrays to share the same memory space, and modifications to one array will also affect the other.

If you want to implement the overall assignment of array content, you can use the functions in the standard librarystd::copyorstd::memcpy, at this time, there are two arrays (that is, the addresses are different).

Here is the sample code:

#include <iostream>
#include <algorithm>
#include <cstring>

const int SIZE = 5;  // The size of the array
int main() {
    int arr1[SIZE] = {1, 2, 3, 4, 5};  // Original array    int arr2[SIZE];  // Target array
    // Use std::copy for overall assignment    std::copy(arr1, arr1 + SIZE, arr2);

    // Print the value of arr2    for (int i = 0; i < SIZE; ++i) {
        std::cout << arr2[i] << " ";
    }
    std::cout << std::endl;

    return 0;
}

In the above code, usestd::copyThe function willarr1Copy the content toarr2middle. so,arr1andarr2There will be independent memory space, and modifications to one array will not affect another array.

Run the above code and the output will be:

1 2 3 4 5

This showsarr2Successfully fromarr1The same value is received in the two arrays.

Using standard library containers

If you use standard library containers (such as std::vector, std::array, etc.) in C++, you can directly use the container's assignment operator or copy constructor to copy between arrays.

#include <vector>
std::vector<int> source = {1, 2, 3, 4, 5};
std::vector<int> destination = source;

This approach is suitable for use with standard library containers, which provide convenient copy operations.

Regardless of the method you choose, make sure that the target array is large enough to accommodate elements of the source array, and be careful to avoid out-of-bounds access of the array.

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.