进程 中的 string& insert()函数

str1.insert(pos,str2);

     #include<iostream>
     using namespace std;
     int main()
    {
     string str1= "javat tutorial";
     cout<<"String contains :" <<str1<<'\n';
     cout<<"After insertion, String value is :"<<str1.insert(5,"point");
     return 0;
     } 

#include<iostream>
using namespace std;
int main()
{
string str1 = "C++  is a language";
string str2 = "programming";
cout<<"String contains :" <<str1<<'\n';
cout<<"After insertion, String is :"<< str1.insert(9,str2,0,11);
return 0;
} 

#include<iostream>
using namespace std;
int main()
{
string str = "Maths is favorite subject" ;
cout<<"String contains :"<<str<<'\n';
cout<<"After insertion, String contains :<<str.insert(9,"my",2);
return 0;
}