字符串

 1、初始化

string proverb("Many a mickle make a muckle.");string phrase(proverb,0,13);  //Many a mickle  第一个参数是作为初始化源的string对象名称，第二个参数是string对象起始索引，第三个参数是用作初始值的字符个数

 string phrase="The higher the fewer";string word=phrase.substr(4,6);//higher 第一个参数指定子字符串开始的索引位置，第二个参数指定子字符串中的字符个数

 2、compare()

word.compare("and")如果word大于and返回正整数，等于返回0，小于返回负整数 

string word1="A jackhammer";string word2="jack";if(word1.compare(2,4,word2)==0) //compare第一个参数是word1中子字符串的起始索引位置，第二个参数是子字符串的字符个数，即jackstring word1="A jackhammer";string word2="It is a jack_in_the_box";if(word1.compare(24,word2,8,4)==0)//后两个参数是word2的子字符串的索引位置和长度if(word1.compare(2,4,"jacket",4)==0)//最后一个参数是jacket的前四个字符，即jack  cout <<"Equal"<<endl;  cout <<"Equal"<<endl;  cout <<"Equal" <<endl;

3、搜索字符串

find()返回搜索到的第一个子字符串中第一个字符的索引位置

string sentence="Manners maketh man";string word="man";cout <<sentence.find(word)<<endl;//15cout <<sentence.find('x')<<endl;//string::nposcout <<sentence.find("an",3)<<endl;//16 从指定索引位置搜索cout<<sentence.find("akat",1,2)<<endl;//9 第二个参数是开始搜索的索引位置，第三个参数是第一个参数中提取作为要查找的字符串的字符个数 

 

string sentence="Manners maketh man";string word="an";int count=0;size_t position=0;for(size-t i=0;i<=sentence.length()-word.length();){  position=sentence.find(word,i);  if(positon==string::npos)   break;  count++;  i=position+1;  //允许重叠找到} for(int index=0;(index=text.find(word,index))!=string::npos;index+=word.length(),count++)//不重叠;

 在字符串中搜索字符集合中的字符

// Program 6.10 Searching a string for characters from a set#include <iostream>#include <string>using std::cout;using std::endl;using std::string;int main() {  // The string to be searched  string text = "Smith, where Jones had had \"had had\", had had \"had\"."                " \"Had had\" had had the examiners' approval.";  string separators = " ,.\"\'";                     // Word delimiters  // Find the start of the first word  size_t start = text.find_first_not_of(separators);  size_t end = 0;                                 // Index for the end of a word  // Now find and output the words  int word_count = 0;                              // Number of words  while(start != string::npos) {    end = text.find_first_of(separators, start + 1); // Find end of word第二个参数是要进行搜索的字符串中，从哪里开始搜索    if(end == string::npos)                        // Found a separator?      end = text.length();                         // No, so set to last + 1    cout << text.substr(start, end - start)        // Output the word         << endl;    word_count++;                                  // Increase the count    // Find the first character of the next word    start = text.find_first_not_of(separators, end + 1);  }  cout << "Your string contained "       << word_count << " words."       << endl;  return 0;}

逆向搜索rfind()和find_last_of(),find_last_not_of用法和以上类似

 4、插入、替换、删除字符串

string phrase="We can insert a string.";string words="a string into ";phrase.insert(14,words);phrase.insert(13,words,8,5);phrase.insert(13,"into something",5);phrase.insert(16,7,'*');

 

 

 

 

find()返回搜索到的第一个子字符串中第一个字符的索引位置