See Out "cout" In C++

1
2

string My_Stng="Hello world!\nZeeshan says, \"It's I who can do it!\"";
cout<<My_Stng;   // cout is used  to get sth displayed or printed

The above code script gives you the desired output, to get the length of that string, simply, use the builtin function length() with string name as My_Stng.length() . Actually, cout<<"Hello world!"; is enough to print "Hello world!" , but to print a new line, a character \n is used. Moreover, if you want to print the character " , you have to use a slash \ with it to avoid an error because that symbol " is both the starting and the ending of a string.

Compilers treat both \n and \" as a single character. Hence My_Stng.length() returns $\boxed{50}$ .