1 getline reads string string library
string a;
getline (cin, a); such a read than any of the read character string has to be fast
2
char a[N];
cin.getline (a, size) char string if defined, may be read cin.getline
3 getline function return value and cin function return value as type bool ,, successful read returns true, false otherwise
getline reads and puts special string when read as a line break or end for reading a certain number of bytes, the space can be read.