演示文件IO的例子

#include<iostream>#include<fstream>#include<string>#include<cassert>#include<cfloat>using namespace std;int main(){//-------------输入部分------------------cout<<"Enter the name of the input file:";string inputFileName;getline(cin,inputFileName);ifstream fin;fin.open(inputFileName.data());assert(fin.is_open());int count=0;double reading,       max=DBL_MIN,   min=DBL_MAX,   sum=0.0;for(;;){fin>>reading;if(fin.eof()) break;count++;sum+=reading;if(reading<min)min=reading;if(reading>max)max=reading;}fin.close();//--------------输出部分-------------------cout<<"Enter the name of the output file:";string outputFileName;getline(cin,outputFileName);ofstream fout(outputFileName.data());assert(fout.is_open());fout<<"There were "<<count<<"values";if(count>0)fout<<"\n   range from "<<min        <<" to "<<max<<"\n   and their average is "<<sum/count<<endl;fout.close();cout<<"Processing complete.\n";}