标签：event email namespace yam cat code 书籍 空指针 isp
前言
实现代码的过程中经常需要将文件夹中的所有文件进行重命名，以方便对文件进行处理。
实现过程
1.测试代码；
/************************************************************************ * Copyright(c) 2017 AMY * All rights reserved. * * File: * Brief: * Version: 1.0 * Author: * Email: happyamyhope@163.com * Date: 2017/10/27 * History: * 20171027: ; ************************************************************************/ //------------------------------------------------------------------------- #include <iostream> #include <string> #include <vector> #include "opencv2/opencv.hpp" #include "opencv2/contrib/contrib.hpp" using namespace std; int main() { string oldFolder = "E:\\fatigue_detection\\dataset\\img\\"; string oldType = "*.jpg"; bool addPath = true; cv::Directory dir; vector<string> filenames = dir.GetListFiles(oldFolder, oldType, addPath); string newName; string oldName; string newType = ".png"; for (int i = 0; i < filenames.size(); i++) { oldName = filenames[i]; newName = oldFolder + to_string(i) + newType; ////method1 //char *oldNamePointer, *newNamePointer; //oldNamePointer = (char *)malloc((oldName.size() + 1) * sizeof(char)); //newNamePointer = (char *)malloc((newName.size() + 1) * sizeof(char)); //strcpy(oldNamePointer, oldName.c_str()); //strcpy(newNamePointer, newName.c_str()); //rename(oldNamePointer, newNamePointer); //free(oldNamePointer); //free(newNamePointer); ////method2 char* oldNamePointer = new char[(oldName.size() + 1) * sizeof(char)]; char* newNamePointer = new char[(oldName.size() + 1) * sizeof(char)]; strcpy(oldNamePointer, oldName.c_str()); strcpy(newNamePointer, newName.c_str()); rename(oldNamePointer, newNamePointer); delete [] oldNamePointer; delete [] newNamePointer; } return 0; }
注意，不同类型之间的转换，比如char*和string、const char*和string等.
2.c++中new和delete的使用；
2.1）针对实体：
type_name * point_name = new type_name; delete type_name;
注意，只能使用delete来释放使用new分配的内存；使用delete的关键在于只用于new分配的内存即new的地址.
2.2）针对动态数组：
type_name * point_name = new type_name [num_elements]; delete [] type_name;
注意，数组使用的是方括号[]；
2.3）使用new和delete应遵守的规则：
参考
1.here
2.书籍：c++ Primer Plus.
完
标签：event email namespace yam cat code 书籍 空指针 isp
原文地址：http://www.cnblogs.com/happyamyhope/p/7742814.html
