Utiliser des chaînes en C

#include <string>

string str("chenyufeng",3);  
cout << str << endl;

string str2("chenyufeng",2,3);  
cout << str2 << endl;

// = :字符串赋值  
str2 = "Robert";  
cout << str2 << endl;

// swap:交换两个字符串的值  
  string string1 = "chen";  
   string string2 = "yufeng";  
   swap(string1, string2);  
   cout << "string1 = " << string1 << ";string2 = " << string2 << endl;

// += ,append：在尾部添加字符串  
   string stringOrigin = "chen";  
    string stringAppend = "yufeng";  
    stringOrigin = stringOrigin + stringAppend;  
    cout << "stringOrigin = " << stringOrigin << endl;  
  
    stringOrigin.append("_OK");  
    cout << "stringOriginAppend = " << stringOrigin << endl;

// insert：在指定position插入字符串  
  string stringInsertOrigin = "chenyufeng";  
    stringInsertOrigin.insert(3, "__");  
    cout << "stringInsertOrigin = " << stringInsertOrigin << endl;

// erase: 删除字符 
  string stringEraseOrigin = "chenyufeng";  
   stringEraseOrigin.erase();  
   cout << "stringEraseOrigin = " << stringEraseOrigin << endl;  
  
  
   // clear ：删除全部字符  
  string stringClearOrigin = "chenyufeng";  
   stringClearOrigin.clear();  
   cout << "stringClearOrigin = " << stringClearOrigin << endl;

// replace: 替换字符串,某个pos位置开始的size个字符替换成后面的“”字符串  
   string stringReplaceOrigin = "chenyufeng";  
    stringReplaceOrigin.replace(3, 2, "66");  
    cout << "stringReplaceOrigin = " << stringReplaceOrigin << endl;

// ==，<,>,<=,>=:比较字符串  
  string stringLeft = "zhen";  
   string stringRight = "yufeng";  
   if (stringLeft == stringRight)  
   {  
       cout << "equal" << endl;  
   }  
  
   if (stringLeft != stringRight)  
   {  
       cout << "not equal" << endl;  
   }  
  
   if (stringLeft < stringRight)  
   {  
       cout << "stringLeft < stringRight" << endl;  
   }  
  
   if (stringLeft > stringRight)  
   {  
       cout << "stringLeft > stringRight" << endl;  
   }

// size(), length():计算字符串长度  
   string stringCount = "chenyufeng";  
    cout << "stringSize = " << stringCount.size() << endl;  
    cout << "stringLength = " << stringCount.length() << endl;

// empty():判断字符串是否为空  
  string stringIsEmpty = "";  
    string stringNotEmpty = "chen";  
    if (stringIsEmpty.empty())  
    {  
        cout << "stringIsEmpty == empty" << endl;  
    }  
    else  
    {  
        cout << "stringIsEmpty != empty" << endl;  
    }  
  
    if (stringNotEmpty.empty())  
    {  
        cout << "stringNotEmpty == empty" << endl;  
    }  
    else  
    {  
        cout << "stringNotEmpty != empty" << endl;  
    }

// 输入输出stream  
  cout << "请输入一个字符串"<<endl;  
    string stringInput;  
    cin >> stringInput;  
    cout << "stringInput = " << stringInput << endl;

// max_size:  
  string stringMaxSize;  
    cout << "stringMaxSize = " << stringMaxSize.max_size() << endl;

// [],at() :元素存取  
  string stringAt = "chenyufeng";  
    cout << "stringAt[3] = " <<stringAt[3] << endl;  
    cout << "stringAt.at(3) = " << stringAt.at(3) << endl;  
  
    stringAt[3] = &#39;6&#39;;  
    stringAt.at(5) = &#39;9&#39;;  
    cout << "stringAt = " << stringAt << endl;

// compare()  
   string stringCompare = "chenyufeng";  
    int aaa = stringCompare.compare("chen"); // > 0  
    int bbb = stringCompare.compare("chenyufeng"); // == 0  
    int ccc = stringCompare.compare("done"); // < 0  
    cout << "aaa = " << aaa << ";bbb = " << bbb << ";ccc = " << ccc << endl;

// substr  
   string stringSubstr = "chenyufeng";  
   // 从索引为4开始的3个字符 
    cout << "stringSubstr.substr(4,3) = " << stringSubstr.substr(4,3) << endl;  
  
   // 从索引为4开始的所有字符  
  cout << "stringSubstr.substr(4) = " <<stringSubstr.substr(4) << endl;  
  
   // 整个字符  
  cout << "stringSubstr.substr() = " <<stringSubstr.substr() << endl;

// find   
  string stringFind = "chenyufeng";  
    stringFind.find('n');  
    cout << "stringFind.find(&#39;n&#39;) = " << stringFind.find(&#39;n&#39;) << endl;  
  
    cout << "stringFind.find_first_of(&#39;e&#39;) = " << stringFind.find_first_of(&#39;e&#39;) << endl;  
      
    cout << "stringFind.find_last_of(&#39;e&#39;) = " << stringFind.find_last_of(&#39;e&#39;) << endl;