C++ Type Modifiers

In C++, type modifiers are the keywords used to change or give extra meaning to already existing data types. It is added to primitive data types as a prefix to modify their size or range of data they can store.

C++ have 4 type modifiers which are as follows:

Let's understand at each of them one by one.

1. signed Modifier

The signed modifier indicates that the given variable variables can store both positive and negative values. To specify any variable as signed, just add the keyword signed at the start of the variable declaration.

Syntax

signed type name;

It can be used only with integer and character data types.

Example

#include <iostream>
using namespace std;

int main() {
  
  	// Printing the size of normal and signed int
  	cout << "signed int size: " << sizeof(signed int)
      	<< " bytes" << endl;
    cout << "int size: " << sizeof(int) << " bytes";

    return 0;
}

signed int's size: 4 bytes
int's size: 4 bytes

Note: The int datatype is signed by default. So, int can directly be used instead of signed int.

2. unsigned Modifier

The unsigned modifier indicates that the given variables can store only non-negative integer values. Like signed modifier, it is also added at the start of the variable declaration to define the given variable as unsigned.

Syntax

unsigned type name;

Unsigned modifier can only be used with integer and character data types.

Example

#include <iostream>
using namespace std;

int main() {
  
  	// Declaring unsigned integer with negative value
  	unsigned int unsigned_i = -10;
      
  	// Declaring normal integer with negative value
  	int i = -10;
  
  	// Printing the value and size
    cout << "unsigned_i: " << unsigned_i << endl;
  	cout << "unsigned int size: " << sizeof(unsigned_i)
      	<< " bytes" << endl;
    cout << "i: " << i << endl;
    cout << "int size: " << sizeof(i) << " bytes";

    return 0;
}

unsigned_i: 4294967286
unsigned_i's size: 4 bytes
i: -10
i's size: 4 bytes

As we can see, when we assigned some negative value to unsigned integer, the value gets converted to its 2's complement because unsigned types cannot store the negative values.

3. short Modifier

The short keyword decreases the size of the data type in the memory. It leads to the decrease in the range of value that the given data type can store. A variable can be declared as short by adding the short keyword before the variable declaration.

Syntax

short type name;

The short keyword can only be used with integer data type.

Example

#include <iostream>
using namespace std;

int main() {
  
  	// Printing the size of short and normal ints
    cout << "short int size: " << sizeof(short int)
      	<< " bytes" << endl;
  	cout << "int size: " << sizeof(int)
      	<< " bytes";
    return 0;
}

short int size: 2 bytes
int size: 4 bytes

Note: The short int can be written as short also. They are equivalent.

4. long Modifier

The long keyword increases the size of the data type in memory. It leads to increase in the range of value that the given data type can store. A variable can be declared as long by adding the long keyword before the variable declaration.

Syntax

long type name;

The long modifier can be used with integer and double data type. It can also be used twice on integers.

Example:

#include <iostream>
using namespace std;

int main() {
  
  	// Printing the size of long and normal ints
  	// double and long double
    cout << "int size: " << sizeof(int)
      	<< " bytes" << endl;
  	cout << "long int size: " << sizeof(long int)
      	<< " bytes" << endl;
  	cout << "double size: " << sizeof(double)
      	<< " bytes" << endl;
  	cout << "long double size: " << sizeof(long double)
      	<< " bytes";
    return 0;
}

int size: 4 bytes
long int size: 8 bytes
double size: 8 bytes
long double size: 16 bytes

Note: The long int can be written as long also. They are equivalent.

Size and Range of Data Types with Modifiers

The below table lists the size and the range of data type (in 64-bit compiler) that is changed with the help of modifiers: