C++ 现代编程风格速查表

栈上数组

// naive:int arr[10];memset(arr, 0, sizeof(a));

// modern:// #include <array>std::array<int, 10> arr;arr.fill(0);

堆上数组

// naive:int *arr = new int[10];memset(arr, 0, 10 * sizeof(int));

// modern:// #include <vector>std::vector<int> arr(10);

字符串

// naive:char str[] = "Hello, C++!";

// modern:// #include <string>std::string str = "Hello, C++!";// or auto str = "Hello, C++!"s;

指向栈的指针

// naive:int ival;int *p = &ival;

// modern:int ival;int &rval = ival;

堆上对象

// naive:MyClass *obj = new MyClass;obj->someMethod(args);

// modern:auto obj = std::make_unique<MyClass>();// or auto obj = std::make_shared<MyClass>();obj->someMethod(args);

函数指针

// naive:typedef int (*func_t)(int, int);func_t func = some_func;

// modern:// #include <function>std::function<int(int, int)> func = some_func;

函数对象

// naive:struct func_t{    int operator() (int arg1, int arg2)    {        // statements    }};func_t func;

// modern:// #include <function>std::function<int(int, int)> func    = [](int arg1, int arg2)    {        // statements    };

宏定义常量

// naive:#define PI 3.14

// modern:const double PI = 3.14;

宏定义类型

// naive:#define uint unsigned int

// modern:typedef unsigned int uint;// or using uint = unsigned int;

宏定义函数

// naive:#define max(a, b) ((a)>(b)?(a):(b))

// modern:template<T>inline T max(T a, T b){    return a>b? a: b;}

原生类型转换

// naive:int ival;double dval = (double)ival;char *pc1 = ...;const char *cpc = (char *)pc1;char *pc2 = (const char *)cpc;Derived *pd1 = ...;Base *pb = (Base *)pd1;Derived *pd2 = (Derived *)pb;void *pv1 = ...;long lval = (long)pv1;void *pv2 = (void *)lval;

// modern:int ival;double dval = static_cast<double>(ival);char *pc1 = ...;const char *cpc = const_cast<const char *>(pc1);char *pc2 = const_cast<char *>(cpc);Derived *pd1 = ...;Base *pb = dynamic_cast<Base *>(pd1);Derived *pd2 = dynamic_cast<Derived *>(pb);void *pv1 = ...;long lval = reinpreter_cast<long>(pv1);void *pv2 = reinpreter_cast<void *>(lval);

线程

// naive:// #include <pthread.h>pthread_t tid;pthread_create(&tid, func, arg);

// modern:// #include <thread>std::thread thr(func, arg);

未完待续…