C和C++文本读写速度对比

读到CSDN论坛中有一个关于C和C++文本读写速度的问题，帖子网址为/topics/260005411#new_post 。网友测试结果为C语言的执行速度要优于C++，本文对此感到不太相信，于是在自己的电脑上进行了验证。验证平台是笔记本Ubuntu操作系统。g++编译，均采用O3优化等级。测试文本大小为842M。

g++ -O3 test.cpp -o test

C++方式代码如下

#include<fstream>#include<sstream>#include<iostream>#include<string>std::string file_in = "/home/xuehen/project/liblinear/featuresForEachRegion_train_0.txt";int main(int argc,char **argv){std::ofstream ofile;std::ifstream ifile;int BuSize=1024*1024*2;int t1=0,t2=0;char* Buffer=new char[BuSize];ifile.open(file_in.c_str(),std::ios::in);ofile.open("Data2.txt",std::ios::out);while(!ifile.eof()){ifile.read(Buffer,BuSize);ofile.write(Buffer,ifile.gcount());}ifile.close();ofile.close();delete []Buffer;return 0; }

time ./testreal 0m30.055suser 0m0.019ssys 0m1.794s

C语言代码如下

#include<fstream>#include<sstream>#include<iostream>#include<string>std::string file_in = "/home/xuehen/project/liblinear/featuresForEachRegion_train_0.txt";int main(int argc,char **argv){FILE *fhr=NULL,*fhw=NULL;int BuSize=1024*1024*2,DataSize=0;int t1=0,t2=0;char* Buffer=new char[BuSize];fhr=fopen(file_in.c_str(), "r");fhw=fopen("Data1C.txt","w");while(!feof(fhr)){DataSize=fread(Buffer,sizeof(char),BuSize,fhr);fwrite(Buffer,sizeof(char),DataSize,fhw);}fclose(fhr);fclose(fhw);delete []Buffer;return 0; }

time ./testreal 0m32.718suser 0m0.008ssys 0m1.938s

从两次结果看C和C++的执行效率基本一致。