vector2.cpp

C++向量类使用示例

最新推荐文章于 2024-06-17 16:34:11 发布

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#vector #statistics #iostream

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本文通过一个C++程序示例展示了如何使用STL中的向量类(vector)进行动态内存分配、添加元素、获取向量大小及容量等基本操作，并演示了如何预留存储空间(reserve)和调整向量大小(resize)。

#ifdef __BCPLUSPLUS__
#include <iostream.h>
#include <vector.h>
#else
#include <iostream>
#include <vector>
#endif

using namespace std;
typedef vector<int> INTVECTOR;

void main(void)
{
// Dynamically allocated vector begins with 0 elements.
INTVECTOR theVector;

// Add one element to the end of the vector, an int with the value 42.
theVector.push_back(42);

   // Show statistics about vector.
   cout << "theVector's size is: " << theVector.size() << endl;
   cout << "theVector's maximum size is: " << theVector.max_size()<< endl;
   cout << "theVector's capacity is: " << theVector.capacity() << endl;

   // Ensure there's room for at least 1000 elements.
   theVector.reserve(1000);
   cout << endl << "After reserving storage for 1000 elements:" << endl;
   cout << "theVector's size is: " << theVector.size() << endl;
   cout << "theVector's maximum size is: " << theVector.max_size()<< endl;
   cout << "theVector's capacity is: " << theVector.capacity() << endl;

   // Ensure there's room for at least 2000 elements.
   theVector.resize(2000);
   cout << endl << "After resizing storage to 2000 elements:" << endl;
   cout << "theVector's size is: " << theVector.size() << endl;
   cout << "theVector's maximum size is: " << theVector.max_size()<< endl;
   cout << "theVector's capacity is: " << theVector.capacity() << endl;
}