why this code give me inncorrect answer..??

Question

#include <iostream>

using namespace std;

int main()

{

int a ;

int b ;

int c ;

//the rule of the operation

c = a + (2*b) ;

// the code

cout<< "enter the value of (a) number \n " ;

cin>> a ;

cout<< "enter the value of (b) number \n " ;

cin>> b ;

cout<< "the value of (c) nwmber equal"<< c<<"\n" ;

}

Answer 1

#include <iostream>

using namespace std;

int main()

{

int a,b,c=0,d=0;

//c=a+(2*b);

// the code

cout<< "enter the value of (a) number \n ";

cin>>a;

cout<< "enter the value of (b) number \n ";

cin>> b ;

d=2*b;

c=a+d;

cout<<"the value of (c) nwmber equal"<<c<<"\n";

return 0;

}

Answer 2

#include <iostream>

using namespace std;

int main()

{

int a ;

int b ;

int c ;

// the code

cout<< "enter the value of (a) number \n " ;

cin>> a ;

cout<< "enter the value of (b) number \n " ;

cin>> b ;

cout<< "the value of (c) nwmber equal"<< c<<"\n" ;

//the rule of the operation

c = a + (2*b) ;
return 0;
}

//Error Was That You Cannot Perform Mathmatical Terms Before Given Values