Primitive or Fundamental Data Types

Integer data type

The integer data type comprises all positive and negative whole numbers. We use the int keyword to define the integer data type. A variable of int type is allocated 4 bytes of memory. It can store any value from -2³¹ to 2³¹-1.

int integer_number = 100;

💡Do you know? If you store 100.5 in a variable of integer type, it would be truncated to 100.

Floating-point data type

The floating-point data type contains a number with a fractional part. We use the float keyword to define the floating-point data type. A variable of a float type is allocated 4 bytes of memory. It can store any value in the range of $±3.40$ x $10^{±38}$.

float float_number = 10.7;

Double data type

The double data type contains the number with the fractional part. We use the double keyword to define the double data type. A variable of double type is allocated 8 bytes of memory. It can store any value in the range of $±1.79$ x $10^{±308}$.

double double_number = 10.65417;

Difference between float and double

The precision of a floating-point number is the number of digits that can be stored after a decimal point. A float can store seven digits after a decimal point precisely. Whereas, double can store 15 digits after a decimal point precisely. It is recommended to use double for floating-point values.

📝Note: We can store a scientific number in double or float data types. The number after e shows the power of 10.

Example program

Run the code below and see the output!