c++ - Creating a default constructor for a stack -

i working on project class requires implement stack integer use calculator. having problems default constructor , wondering missing.

operandstack(int stacksize)     {         if (stacksize<=0)             {cout<<"must positive"<<endl;}         this->capacity=capacity;         s =new double[stacksize];         t=0;     } 

thanks help.

" having problems default constructor , wondering missing."

a default constructor takes no parameters, or declares default values of them. cite linked reference documentation

default constructors

a default constructor constructor can called no arguments (either defined empty parameter list, or default arguments provided every parameter).

thus implementation should like:

class operandstack { public:      operandstack(int stacksize = 10)                               // ^^^^ declare default value      // better use member initializer list, instead of initializing claas      // members inside constructor's body:      : capacity(stacksize), s(new double[stacksize]), t(0) {         if (stacksize<=0) {cout<<"must positive"<<endl;}         // ^^^^ better use exception instead of         //      output statement (it's ok basic debugging)      } };