an empty string:
A string initialized to Hello:Hello
A string initialized to previous string:Hello
A string initialized to (previous string, 1, 2):el
A string initialized to @:@
A string initialized to 20:20
n = 20 atoi(n) = 20 atof(n) = 20
z = x + y = Helloworld
x += y; x = Helloworld
y.insert (0, x); y = Helloworld
x = x + y + x; x = HelloworldHello
x = y + x + x; x = worldHelloHello
z = x + s +  + y.substr (y.find (w), 1) + y.substr (y.find (w) + 1) + . = Hello, world.
ch = x[0] = H
z = x.substr (2, 3) = llo
x.replace (2, 2, r); x = Hero
x.replace (0, 1, 'j'); x = jello
enter a word:word =abcdefghijklmnopqrstuvwxyz length = 26

End of test