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(C++) Variable

 

A variable is something to store data in. This data can be of any data type. The name of the variable is called its identifier.

 

Don't declare a variable until you have a value to initialize it with [1].

 

In the code example below, there are two variables, 'number' and 'i':

 

#include <iostream>

int main()
{
  int number = 0;
  for (int i = 0; i!=10; ++i)
  {
    number+=i;
    std::cout << i << " : " << number << std::endl;
  }
}

 

This produces the following screen output:

 

0 : 0
1 : 1
2 : 3
3 : 6
4 : 10
5 : 15
6 : 21
7 : 28
8 : 36
9 : 45

 

The scope of the variable 'number' is from the line it is declared to the end of main.

The scope of the variable 'i' is inside the for-loop.

 

 

 

 

 

References

 

  1. Bjarne Stroustrup. The C++ Programming Language (3rd edition). 1997. ISBN: 0-201-88954-4. Item 6.5.10: 'Don't declare a variable until you have a value to initialize it with'.

 

 

 

 

 

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