C++ Data Types C-PLUS-PLUS
- C++ Introduction
- C++ Syntax
- C++ Output (cout <<)
- C++ Comments
- C++ Variables
- C++ User Input
- C++ Data Types
- C++ Operators
- C++ Strings
- C++ Math
- C++ Booleans
- C++ If Else
- C++ Switch
- C++ While Loop
- C++ Do/While Loop
- C++ For Loop
- C++ Break and Continue
- C++ Arrays
- C++ References
- C++ Pointers
- C++ Functions
- C++ Functions Parameters
- C++ Function Overloading
- C++ OOP
- C++ Classes and Objects
- C++ Class Methods
- C++ Constructors
- Destructors in C++
- C++ Access Specifiers
- C++ Encapsulation
- C++ Inheritance
- C++ Polymorphism
- C++ Files
- C++ Exception Handling
C++ Data Types
C++ Data Types
The data type specifies the size and type of information the variable will store:
Data Type | Size | Description |
---|---|---|
int |
4 bytes | Stores whole numbers, without decimals |
float |
4 bytes | Stores fractional numbers, containing one or more decimals. Sufficient for storing 7 decimal digits |
double |
8 bytes | Stores fractional numbers, containing one or more decimals. Sufficient for storing 15 decimal digits |
boolean |
1 byte | Stores true or false values |
char |
1 byte | Stores a single character/letter/number, or ASCII values |
Example
#include <iostream>
#include <string>
using namespace std;
int main () {
// Creating variables
int myNum = 5; // Integer (whole number)
float myFloatNum = 5.99; // Floating point number
double myDoubleNum = 9.98; // Floating point number
char myLetter = 'D'; // Character
bool myBoolean = true; // Boolean
string myString = "Hello"; // String
// Print variable values
cout << "int: " << myNum << "\n";
cout << "float: " << myFloatNum << "\n";
cout << "double: " << myDoubleNum << "\n";
cout << "char: " << myLetter << "\n";
cout << "bool: " << myBoolean << "\n";
cout << "string: " << myString << "\n";
return 0;
}
Output:
int: 5
float: 5.99
double: 9.98
char: D
bool: 1
string: Hello
Scientific Numbers
A floating point number can also be a scientific number with an "e" to indicate the power of 10:
Example
#include <iostream>
using namespace std;
int main () {
float f1 = 35e3;
double d1 = 12E4;
cout << f1 << "\n";
cout << d1;
return 0;
}
Output:
35000
120000
Booleans
A boolean data type is declared with the bool
keyword and can only take the values true
or false
. When the value is returned, true
= 1
and false
= 0
.
Example
#include <iostream>
using namespace std;int main() {
bool isCodingFun = true;
bool isFishTasty = false;
cout << isCodingFun << "\n";
cout << isFishTasty;
return 0;
}
Output:
1
0
Characters
The char
data type is used to store a single character. The character must be surrounded by single quotes, like 'A' or 'b':
Example
#include <iostream>
using namespace std;
int main () {
char myGrade = 'D';
cout << myGrade;
return 0;
}
Output:
D
Char datatype with ASCII values
You can also use ASCII values to display certain characters.
Example
#include <iostream>
using namespace std;
int main () {
char a = 65, b = 66, c = 67;
cout << a;
cout << b;
cout << c;
return 0;
}
Output:
ABC
ASCII values 65 to 90 for uppercase A to Z
ASCII values 97 to 122 for lowercase a to z
Strings
The string
type is used to store a sequence of characters (text). This is not a built-in type, but it behaves like one in its most basic usage. String values must be surrounded by double-quotes.
To use strings, you must include an additional header file in the source code, the <string>
library.
Example
#include <iostream>
#include <string>
using namespace std;int main() {
string greeting = "Hello";
cout << greeting;
return 0;
}
Output:
Hello