What is the difference between arrays and vectors in C++?

In C++, an array is a fixed-size data structure whose size needs to be specified at creation time, while a vector is a dynamic-sized data structure whose size can be changed at runtime. Arrays use the [] operator to access and modify elements, while vectors use the push_back() method to add elements and the [] operator to access elements. Arrays need to use delete[] to release memory, while vectors use erase() to delete elements.

Arrays and Vectors in C++: Differences and Practical Combat

In C++, arrays and vectors are used to store the same A collection of type data. However, they have some key differences in how they create, access, and manage data.

Array

An array is a fixed-size data structure whose size is specified when it is created. Use the [] operator to access and modify elements in an array.

int myArray[5] = {1, 2, 3, 4, 5};

cout << myArray[2]; // 输出 3
myArray[3] = 10;  // 将元素 4 替换为 10

Vector

A vector is a dynamically sized data structure whose size can change at runtime. Use the push_back() method to add elements and the [] operator to access and modify elements.

vector<int> myVector; // 创建一个空向量

myVector.push_back(1);
myVector.push_back(2);
myVector.push_back(3);

cout << myVector[1]; // 输出 2
myVector[2] = 10;  // 将元素 3 替换为 10

Difference

##CharacteristicsArrayVectorSizeFixedDynamicCreateNeed to specify the sizeNo need Specify sizeAdd elementsUse myArray[index]Use myVector.push_back()Delete elementUse delete[] myArray;Use myVector.erase()##Practical case

Calculate the average using an array

int main() {
    int myArray[5] = {1, 2, 3, 4, 5};

    int sum = 0;
    for (int i = 0; i < 5; i++) {
        sum += myArray[i];
    }

    double average = (double)sum / 5;

    cout << average << endl;

    return 0;
}

Use a vector to store student scores

int main() {
    vector<int> scores;

    scores.push_back(85);
    scores.push_back(90);
    scores.push_back(95);

    for (vector<int>::iterator it = scores.begin(); it != scores.end(); it++) {
        cout << *it << endl;
    }

    return 0;
}

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