#include <iostream>
#include <string>
int main() {
    string in_string;
    // 向用户终端写字符串
    std::cout << "Please enter your name: ";
    // 把用户输入的读取到 in_string 中
    std::cin >> in_string;
    if ( in_string.empty() )
    // 产生一个错误消息输出到用户终端
    std::cerr << "error: input string is empty!\n";
    else std::cout << "hello, " << in_string << "!\n";
}

#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
int main()
{
    string ifile;
    cout << "Please enter file to sort: ";
    cin >> ifile;
    // 构造一个 ifstream 输入文件对象
    ifstream infile( ifile.c_str() );
    if( ! infile ) {
        cerr << "error: unable to open input file: " << ifile << endl;
        return -1;
    }
    string ofile = ifile + ".sort";
    // 构造一个 ofstream 输出文件对象
    ofstream outfile( ofile.c_str() );
    if( !outfile ) {
      cerr << "error: unable to open output file: " << ofile << endl;
      return -2;
    }
    string buffer;
    vector<string> text;
    int cnt = 1;
    while ( infile >> buffer ) {
        text.push_back( buffer );
        cout << buffer << ( cnt++ % 8 ? " " : "\n" );
    }
    sort( text.begin(), text.end() );
    // ok: 把排序后的词打印到 outfile
    vector<string>::iterator iter = text.begin();
    for ( cnt = 1; iter != text.end(); ++iter, ++cnt )
        outfile << *iter << (cnt%8 ? " " : "\n" );
    return 0;
}

#include <sstream>
string program_name( "our_program" );
string version( "0.01" );
// ...
string mumble( int *array, int size )
{
    if ( ! array ) {
        ostringstream out_message;
        out_message << "error: "
        << program_name << "--" << version
        << ": " << __FILE__ << ": " << __LINE__
        <<" -- ptr is set to 0; "
        << " must address some array.\n";
        // 返回底层 string 对象
        return out_message.str();
}

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
string pooh_pals[] = {
"Tigger", "Piglet", "Eeyore", "Rabbit"
};
int main()
{
    vector<string> ppals( pooh_pals, pooh_pals+4 );
    vector<string>::iterator iter = ppals.begin();
    vector<string>::iterator iter_end = ppals.end();
    cout << "These are Pooh's pals: ";
    // 把每个元素拷贝到 cout ...
    ostream_iterator< string > output( cout, " " );
    copy( iter, iter_end, output );
    cout << endl;
}

#include <iostream>
#include <string>
int main()
{
    int item_number;
    string item_name;
    double item_price;
    cout << "Please enter the item_number, item_name, and price: " << endl;
    cin >> item_number;
    cin >> item_name;
    cin >> item_price;
    cout << "The values entered are: item# "
        << item_number << " "
        << item_name << " @$"
        << item_price << endl;
}

#include <algorithm>
#include <string>
#include <vector>
#include <iostream>
int main()
{
    istream_iterator< string > in( cin ), eos ;
    vector< string > text ;
    // 从标准输入向 text 拷贝值
    copy( in , eos , back_inserter( text ) ) ;
    sort( text.begin() , text.end() ) ;
    // 删除所有重复的值
    vector< string >::iterator it ;
    it = unique( text.begin() , text.end() ) ;
    text.erase( it , text.end() ) ;
    // 显示结果 vector
    int line_cnt = 1 ;
    for ( vector< string >::iterator iter = text.begin();
    iter != text.end() ; ++iter , ++line_cnt )
    cout << *iter
        << ( line_cnt % 9 ? " " : "\n" ) ;
    cout << endl;
}

#include <iostream>
int main()
{
    int ch;
    // 或使用:
    // while (( ch = cin.get() ) && ch != EOF)
    while (( ch = cin.get()) != EOF)
    cout.put(ch);
    return 0;
}

#include <iostream>
int main()
{
    const int max_line = 1024;
    char line[ max_line ];
    while ( cin.get( line, max_line ))
    {
        // 最大读取数量 max_line - 1, 也可以为 null
        int get_count = cin.gcount();
        cout << "characters actually read: "
        << get_count << endl;
        // 处理每一行
        // 如果遇到换行符
        // 在读下一行之前去掉它
        if ( get_count & max_line-1 )
            cin.ignore();
     }
}

#include <iostream>
int main()
{
    const lineSize = 1024;
    int lcnt = 0; // 读入多少行
    int max = -1; // 最长行的长度
    char inBuf[ lineSize ];
    // 读取 1024 个字符或者遇到换行符
    while (cin.getline( inBuf, lineSize ))
    {
         // 实际读入多少字符
         int readin = cin.gcount();
         // 统计: 行数最长行
         ++lcnt;
         if ( readin > max )
             max = readin;
         cout << "Line #" << lcnt
             << "\tChars read: " << readin << endl;
         cout.write( inBuf, readin).put('\n').put('\n');
     }
     cout << "Total lines read: " << lcnt << endl;
     cout << "Longest line read: " << max << endl;
}

char ch, next, lookahead;
while ( cin.get( ch ))
{
    switch (ch) {
    case '/':
     // 是注释行吗? 用 peek() 看一看:
     // 是的? ignore() 余下的行
     next = cin.peek();
     if ( next == '/' )
         cin.ignore( lineSize, '\n' );
     break;
     case '>':
     // 查找 >>=
     next = cin.peek();
     if ( next == '>' ) {
         lookahead = cin.get();
         next = cin.peek();
     if ( next != '=' )
     cin.putback( lookahead );
}

#include <iostream>
#include "WordCount.h"
/* 必须修改 WordCount, 指定输入操作符为友元
class WordCount {
    friend ostream& operator<<( ostream&, const WordCount& );
    friend istream& operator>>( istream&, WordCount& );
*/
istream&
operator>>( istream &is, WordCount &wd )
{
/* WordCount 对象被读入的格式:
 * <2> string
 * <7,3> <12,36>
 */
int ch;
/* 读入小于符号, 如果不存在
 * 则设置 istream 为失败状态并退出
 */
if ((ch = is.get()) != '<' )
{
    is.setstate( ios_base::failbit );
    return is;
}
 // 读入多少个
 int occurs;
 is >> occurs;
 // 取 >; 不检查错误
 while ( is && (ch = is.get()) != '>' );
 is >> wd._word;
 // 读入位置
 // 每个位置的格式: < line, col >
 for ( int ix = 0; ix < occurs; ++ix )
 {
  int line, col;
  // 提取值
  while (is && (ch = is.get())!= '<' );
  is >> line;
  while (is && (ch = is.get())!= ',' );
  is >> col;
  while (is && (ch = is.get())!= '>' );
  wd.occurList.push_back( Location( line, col ));
 }
 return is;
}