c++ primer 第五版第八章答案

8.1  8.2

/*
* c++ primer exercise.
* test file.
*/ 

#include <iostream>
using namespace std;


istream & read_write(istream &in)
{
//   char cval;
    int ival;
    while(in>>ival)
        cout<<ival<<' ';
    in.clear();
    return in;

}


int main(int argc, char* argv[])
{
    
    read_write(cin);
    
    system("pause");
    return 0;
}

8.3 读取类型不匹配，EOF，发生系统级不可恢复的状态。

8.4
/*
* c++ primer exercise.
* test file.
*/ 

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
using namespace std;





int main(int argc, char* argv[])
{
    
    string sval;
    vector<string> svec;
    ifstream in(*(argv+1));
    if(in){
        while(getline(in,sval)){
            svec.push_back(sval);
            //cout<<sval<<endl;
        }
    }else{
        cerr<<"can not open: "+ string(*(argv+1));
        return -1;
    }
    
    for(unsigned int i=0;i<svec.size();++i){
        cout<<svec[i]<<endl;
    }
 
    
    
    system("pause");
    return 0;
}



8.5
/*
* c++ primer exercise.
* test file.
*/ 

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
using namespace std;





int main(int argc, char* argv[])
{
    
    string sval;
    vector<string> svec;
    ifstream in(*(argv+1));
    if(in){
        while(in>>sval){
            svec.push_back(sval);
            //cout<<sval<<endl;
        }
    }else{
        cerr<<"can not open: "+ string(*(argv+1));
        return -1;
    }
    
    for(unsigned int i=0;i<svec.size();++i){
        cout<<svec[i]<<endl;
    }
 
    
    
    system("pause");
    return 0;
}