C++--STL-string容器的使用，学习代码

/* brief:STL中string容器的使用 */ #include <iostream> #include "vector" #include "algorithm" #include "string" using namespace std; void main21() { string s1="aaaa"; string s2("bbbb"); string s3=s2; string s4(10,'a'); cout<<s1<<endl; cout<<s2<<endl; cout<<s3<<endl; cout<<s4<<endl; } void main22()//利用指针输出字符串 { string s1="abcdefg"; for(int i=0;i<s1.length();i++) { cout<<s1[i]<<" "; } for(string::iterator it=s1.begin();it !=s1.end();it++)//利用迭代器输出 { cout<<*it<<" "; } } void main23()//复制指定个数个字符到新的内存中 { string s1="aba";   const char *cfirst = s1.c_str();//注意只读 cout<<*(cfirst+1)<<endl; printf("s1:%s \n",s1.c_str());//返回string首地址 char buf[128]={0}; s1.copy(buf,3,0);//只拷贝3个字符，不会变成C风格字符串 cout<<"buf1"<<buf<<endl; } void main24() { string s1="aaa"; string s2("bbb"); s1=s1+s2; cout<<s1<<endl; string s3="333"; string s4("444"); s3.append(s4);//字符串拼接一下 cout<<s3<<endl; } //字符串的查找和替换 void main25() { /*string s1="wh hooell333 33 33 wgh ddsfds  88d"; int  index=s1.find("333",0); cout<<index<<endl; int offindex =s1.find("333",0); while(offindex != string::npos) { cout<<offindex<<endl; offindex=offindex+1; offindex=s1.find("333",offindex); */ string s1="wh hooell333 33 33 wgh ddsfds  88d"; int offindex =s1.find("333",0); while(offindex != string::npos) { cout<<offindex<<endl; s1.replace(offindex,3,"666"); offindex=offindex+1; offindex=s1.find("333",offindex); } cout<<s1<<endl; } void main26()//删除一个字符 { string s1="hello world"; string::iterator it=find(s1.begin(),s1.end(),'l'); if( it !=s1.end()) { s1.erase(it); } cout<<s1<<endl; s1.erase(s1.begin(),s1.end()); cout<<s1.length()<<endl; } void main27()//插入元素在指定位置前面 { string s1="hello world"; s1.insert(0,"dddddd"); cout<<s1<<endl; } void main28() { //  transform() } void main() { // main21(); // main22(); // main23(); // main24(); //  main25(); // main26(); main27(); }