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目录
1.总体理解array
C和C++创建数组时,通常会使用new和delete来管理空间
C++11提供了 一种新的思路,#include <array> ,这种办法执行效率甚至比vector都高,这样我们不用自己再管理内存
2.具体理解array
假设 现在使用array对象来 存储一年四季的开支,也就是4个
std::array<double, 4> expenses; //array包含在std空间中,同时我们需要 包含头文件array
假如需要显示expenses 包含的内容,直接可以 show( expenses );即可
假如需要修改expenses,则需要传递地址给函数(或者传递引用):fill( &expense );
show和fill的原型是什么?
void show(std::array<double, 4> da);
void fill(std::array<double, 4> *pa);
同时,还可以包含一些其他 编程思想和技巧
const int Seasons = 4; //符号常量替换4
其次,使用一个const array 对象,该对象包含4个string对象,用于表示四个季度
const std::array<std::string, Season> Snames =
{"Spring", "Summer", "Fall", "Winter"};
3.array程序示例
//本程序是示例C++11中array用法
#include <iostream>
#include <array>
#include <string>
//constant data
const int Season = 4;
const std::array<std::string, Season> Snames = {"Spring", "Summer", "Fall", "Winter"};
//function
void fill(std::array<double, Season> * pa);
void show(std::array<double, Season> da);
int main()
{
std::array<double, Season> expenses;
fill(&expenses);
show(expenses);
system("pause");
return 0;
}
void fill(std::array<double, Season> * pa)
{
using namespace std;
for (int i = 0; i < Season; i++)
{
cout << "Enter " << Snames[i] << " expenses: ";
cin >> (*pa)[i];
}
}
void show(std::array<double, Season> da)
{
using namespace std;
double total = 0.0;
cout << "\nEXPENSES\n";
for (int i = 0; i < Season; i++)
{
cout << Snames[i] << ": $" << da[i] << endl;
total += da[i];
}
cout << "Total Expenses: $" << total << endl;
}
运行结果: