I have a tiny .h file:
#include "stdafx.h" #ifndef BIGNUM_H #define BIGNUM_H #include <vector> class bignum{ private: std::vector<int> num; num.resize(4); }; #endif I get the following error messages:
What am I missing?
You can't call a method on a member variable inside your class declaration. If you want to resize the vector to 4 do so in the class constructor (or in another function but the constructor is by far the best place to do so).
In your cpp file you could do something like:
bignum::bignum() { num.resize(4); } or:
bignum::bignum(): num(4) {} The second one calls the vector constructor that takes a size argument. Or you can directly do it in your .h file:
class bignum{ bignum(): num(4) {} // version 1 bignum(): num() { num.resize(4); } // version 2 private: std::vector<int> num; }; You cannot call num.resize(4); outside of a function. You could use your class' constructor, or a C++11 initialization at the point of declaration.
class bignum { private: std::vector<int> num = std::vector<int>(4); // C++11 }; class bignum { bignum() : num(4) {} // C++03 and C++11 private: std::vector<int> num; }; 
