C++ Primer For Java Programmers

Variable Declarations

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As in all programming languages, we use identifiers to name things such as variables, functions, data types, classes, etc. Identifiers in C++:

  • can consist of characters, digits, and the underscore
  • must begin with a character
  • are case sensitive
  • can be of any length, though the first 32 characters must be unique.


Variables in C++ must be explicitly declared as they are in Java.

int grade,

double average,

In C++, variables are not initialized when they are created. You can declare a variable and initialize it at the same time

int total = 0;
double taxRate = 0.05;

Data Types

C++ provides a number of primitive data types including

char 1-byte signed
short 2-bytes signed
int size of system word
(4-bytes: 32-bit architecture)
(8-bytes: 64-bit architecture)
long 4-bytes signed
long long 8-bytes signed
(implemented in software)
unsigned char 1-byte unsigned
unsigned short 1-byte unsigned
unsigned short 2-bytes unsigned
unsigned int same size as an int
unsigned int 4-bytes unsigned
unsigned long long 8-bytes unsigned
(implemented in software)
float 4-bytes
double 8-bytes
long double 12-bytes
bool 4-bytes
enum 8-bytes
reference same size as an int

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Last modified: April 27, 2007, at 04:24 PM.