Initialization of variables

When declaring a regular local variable, its value is by default undetermined. But you may want a variable to store a concrete value at the same moment that it is declared. In order to do that, you can initialize the variable. There are two ways to do this in C++:
The first one, known as c-like, is done by appending an equal sign followed by the value to which the variable will be initialized:
type identifier = initial_value ;
For example, if we want to declare an int variable called a initialized with a value of 0 at the moment in which it is declared, we could write:
int a = 0;
The other way to initialize variables, known as constructor initialization, is done by enclosing the initial value between parentheses (()):
type identifier (initial_value) ;
For example:
int a (0);
Both ways of initializing variables are valid and equivalent in C++.

// initialization of variables
#include <iostream>
using namespace std;
int main ()
{
int a=5; // initial value = 5
int b(2); // initial value = 2
int result; // initial value
undetermined
a = a + 3;
result = a - b;
cout << result;
return 0;
}