c++ - class with float variable -

i have simple class here variable. why not return value of variable 10.5?

output

test! -1.09356e+09 

code

#include "iostream"  using namespace std;  class txtbin{     protected:         float area;      public:         txtbin();         float get_area(); };  txtbin::txtbin(){     float area = 10.5; }  float txtbin::get_area(){     return area; }  int main(int argc, char* argv[]){     txtbin a;     cout << "test! " << a.get_area() << endl;      return 0; } 

this creating local variable, not initializing member:

txtbin::txtbin(){     float area = 10.5; // creates variable called area isn't used. } 

you should initialize member this

txtbin::txtbin() : area(10.5) { } 

or perhaps directly in class if using c++11 or newer:

class txtbin{     protected:         float area = 10.5;      public:         txtbin();         float get_area(); };