《C++primer》v5 第8章 IO库 读书笔记 习题答案

istream &read(istream &is)
{
    int a;
    auto old_state=is.rdstate();
    is.clear();
    is>>a;
    is.setstate(old_state);
    return is;
}
int main()
{
    read(cin);
    return 0;
}

#include<fstream>
using namespace std;
int main()
{
    ifstream in("ifile.txt");
    vector<int> vec;
    int a;
    while(in>>a)
        vec.push_back(a);
    for(auto i:vec)
        cout<<i<<endl;
    return 0;
}

#include<fstream>
using namespace std;
int main()
{
    ifstream in("ifile.txt");
    vector<string> vec;
    string s;
    while(in>>s)
        vec.push_back(s);
    for(auto i:vec)
        cout<<i<<endl;
    return 0;
}

#include<sstream>
using namespace std;
istream &read(istream &is)
{
    string s;
    auto old_state=is.rdstate();
    is.clear();
    while(is>>s)
        cout<<s<<endl;
    is.setstate(old_state);
    return is;
}
int main()
{
    string s;
    getline(cin,s);
    istringstream is(s);
    read(is);
    return 0;
}

#include<fstream>
#include<sstream>
using namespace std;
int main()
{
    fstream in("ifile.txt");
    string s;
    vector<string> vec;
    while(getline(in,s))
    {
        vec.push_back(s);
    }
    for(auto &c:vec)
    {
        istringstream isout(c);
        string word;
        while(isout>>word)
            cout<<word<<endl;
    }
    return 0;
}

#include<fstream>
#include<sstream>
using namespace std;
int main()
{
    fstream in("ifile.txt");
    string s;
    vector<string> vec;
    while(getline(in,s))
    {
        vec.push_back(s);
    }
    istringstream isout;
    for(int i=0; i<vec.size(); ++i)
    {
        isout.clear();
        isout.str(vec[i]);
        string word;
        while(isout>>word)
            cout<<word<<endl;
    }
    return 0;
}