C++ Struct member string array, expected an expression -

my string array giving error "expected expression" , i'm not understanding why:

#include <iostream> #include <string> #include <sstream>  using namespace std;  typedef struct {     string title;     string cells[]; } menu;  menu mainm, dpe, dps, dpes, tec, rt, wc, mc, mn, cl, imp, dr, df, pd, ts;  int main() {     mainm.title = "menu principal";     mainm.cells[] = { "dispositivos de entrada", "dispositivos de saida", "dispositivos de entrada e saida" };  } 

the error @ mainm.cells[]

severity code description project file line error (active) expected expression arpsis f:\c++\arpsis\arpsis\testes.cpp 16

in c++, line ill-formed:

 mainm.cells[] = { "dispositivos de entrada", "dispositivos de saida", "dispositivos de entrada e saida" }; 

when declare arrays, may use [] signify fact, when isn't part of declaration, , aren't indexing it, shouldn't use [] @ when referring array.

(as jonathan potter points out, struct definition ill-formed:

typedef struct {     string title;     string cells[]; } menu; 

think -- if supposed complete definition of menu structure, taking size sizeof should possible. if size of cells has not been determined yet isn't possible yet.

you can use [] without specifying size, when initializing array list of items, because compiler count items you. if aren't doing that, it's not going work.)

changing code to

mainm.cells = { "dispositivos de entrada", "dispositivos de saida", "dispositivos de entrada e saida" }; 

gives more intelligible error message:

http://coliru.stacked-crooked.com/a/6279ed5446008616

main.cpp:16:17: error: assigning array initializer list

when initializing array, can use braced expressions initialization form, after initialization, can't anymore, need use loop, or memcpy or something.

if on c++11 standard, , use vector instead of array, can pretty close wanted, this: http://coliru.stacked-crooked.com/a/e7d6964388bf42ac

or if want stick arrays use std::array , use std::copy initialize copying, here. http://coliru.stacked-crooked.com/a/3caac3676c94d913