#include <string>                    // header file for strings

string st2, st3;
string st = "abcdefg";

st2 = st[4];                         // st2 == `e`
st3 = st + st2;                      // abcdefge

st.empty()                           // false

st[2] = '*';                         // st == ab*defg
st.at(5) = '-';                      // st == ab*de-g

string str11 = "abcdefghi";
string str12 = "0123";
str11.insert (3,str12);              // "abc0123defghi"
str12.insert (1,"XYZ");              // "0XYZ12"

string str13 = "abcdefghi";
str13.erase (5,3);                   //  "abcdei"

string str14 = "abcdefghi";
string str15 = "XYZ";
str14.replace (4,2,str15);           // "abcdXYZghi"

string str16 = "abcdefghi";
string str17 = "def";
int pos = str16.find (str17,0);      // 3

pos = str16.find ("AB",0);           // Not found

string str18 = "abcdefghi";
string str19 = str18.substr (6,2);   // gh

#include <fstream>
string line;
ifstream infile ("Stringtest.txt");
while (getline(infile,line)) { code }

#include <string>         // string st
#include <cstring>        // strcpy
using namespace std;      // string st
char ar[20];
string st = "abcde";     // a C++ string
strcpy(ar,st.c_str());   // ar is a|b|c|d|e|null|...