C++ Data Types
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Integer Type
The int type stores whole numbers with no fractional component, and on most modern 32-bit and 64-bit systems it occupies 4 bytes, giving it a range of roughly -2 billion to +2 billion. Use int for counters, indexes, and any value that will never need a decimal point.
Example: Integer Type
#include <iostream>
int main() {
int counter = 2000000;
std::cout << "Counter: " << counter << std::endl;
return 0;
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Character Type
The char type stores a single character in exactly 1 byte, using single quotes like A rather than the double quotes used for full strings. Internally, a char is really just a small integer representing that character's position in the ASCII table, which is why you can perform arithmetic directly on characters.
Example: Character Type
#include <iostream>
int main() {
char grade = 'A';
std::cout << "Grade: " << grade << std::endl;
return 0;
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Floating-Point Types
float and double both store numbers with a decimal point, but they trade off memory for precision: float uses 4 bytes and roughly 7 significant digits of accuracy, while double uses 8 bytes for about 15-16 digits. Most C++ code defaults to double unless memory is tightly constrained, since the extra precision avoids subtle rounding errors.
Example: Floating-Point Types
#include <iostream>
int main() {
float price = 9.99f;
double pi = 3.14159265358979;
std::cout << price << " " << pi << std::endl;
return 0;
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Boolean Type
The bool type holds only two possible values, true or false, and is the natural type for anything that represents a yes/no condition, like whether a user is logged in. Using bool instead of an int flag (0 or 1) makes conditional code self-documenting, since isLoggedIn reads far more clearly than loggedInFlag == 1.
Example: Boolean Type
#include <iostream>
int main() {
bool isLoggedIn = true;
std::cout << "Logged in: " << isLoggedIn << std::endl;
return 0;
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Void Type
void represents the deliberate absence of a value, most commonly seen as the return type of a function that performs an action but doesn't hand anything back to the caller, like void printMessage(). It's also used in a few lower-level contexts, such as a generic pointer type void* that can point to data of any type.
Example: Void Type
#include <iostream>
void printMessage() {
std::cout << "No value returned" << std::endl;
}
int main() {
printMessage();
return 0;
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