if (choice = "add")

whats wrong with this line
choice is a string variable

i get this error


--------------------Configuration: lessons - Win32 Debug--------------------
Compiling...
test1.cpp
C:\Program Files\Microsoft Visual Studio\MyProjects\lessons\test1.cpp(20) : error C2451: conditional expression of type 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' is illegal
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
Error executing cl.exe.

test1.obj - 1 error(s), 0 warning(s)