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Best Ways to Initialize variables in Java programming - 2022 reviewed



When the variables in the example above are declared, they have an undetermined value until they are assigned a value for the first time. But it is possible for a variable to have a specific value from the moment it is declared. This is called the initialization of the variable.

In C++, there are three ways to initialize variables. They are all equivalent and are reminiscent of the evolution of the language over the years:

The first one, known as c-like initialization (because it is inherited from the C language), consists of appending an equal sign followed by the value to which the variable is initialized:

type identifier = initial_value;
For example, to declare a variable of type int called x and initialize it to a value of zero from the same moment it is declared, we can write:

 
 
int x = 0;



A second method, known as constructor initialization (introduced by the C++ language), encloses the initial value between parentheses (()):

type identifier (initial_value);
For example:

 
 
int x (0);



Finally, a third method, known as uniform initialization, similar to the above, but using curly braces ({}) instead of parentheses (this was introduced by the revision of the C++ standard, in 2011):

type identifier {initial_value};
For example:

 
 
int x {0};



All three 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(3);              // initial value: 3
  int c{2};              // initial value: 2
  int result;            // initial value undetermined

  a = a + b;
  result = a - c;
  cout << result;

  return 0;
}
 
print out
 
6

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