Differences between Float and Double in C

Both float and double are used to represent floating-point numbers in the C programming language, and their precision and storage capacity are the main differences between the two. In this article, you will learn about the difference between float and double in C. But before discussing the differences, you must know about the float and double.

What is Float?

Float uses 32 bits to store its value because it is a single-precision floating-point number. It can represent a range of values with up to 6-7 significant digits and has a precision of roughly six decimal places. Float can be used for the majority of calculations in science and engineering.

Syntax:

Here is the syntax of float in the C programming language:

What is Double?

Double is a double-precision floating-point number, so its value is stored in its 64 bits. It can represent a range of values with up to 15-16 significant digits and has a precision of roughly 15 decimal places. Double works well for calculations that call for greater accuracy, like those in finance or astronomy.

Syntax:

Here is the syntax of double in the C programming language:

Key differences between Float and Double

Double should generally be used for greater precision, while float should be used to conserve memory. However, double consumes twice as much memory as float does, so float might be a better choice if memory consumption is a concern. There are various key differences between Float and Double. Some of the key differences Float and Double are as follows:

• Range: Double can represent values in the range of about 3E-308 to 1.7E+308. In contrast, float can represent values in the range of about 1.2E-38 to 3.4E+38.
• Precision: Due to the differences in how they represent and store values, float and double have varying degrees of precision. Float uses 32 bits to store a value, with one bit set aside for the sign, eight bits for the exponent, and 23 bits for the mantissa. The float can now represent values with up to 6-7 significant Double uses 64 bits to store a value, with one bit set aside for the sign, 11 bits for the exponent, and 52 bits set aside for the mantissa. Double can now represent values with up to 15-16 significant digits.
• Memory: Double takes up 8 bytes (64 bits) of memory, compared to float's 4 bytes (32 bits). In other words, double needs more memory than float.
• Performance: On some systems, float calculations can generally be performed more quickly than double calculations because they require less precision and memory. However, the actual performance disparity will depend on the system in question and the nature of the calculation being done.
• Declaration: In C, the "float" keyword is used before the variable name to declare a float as in "float myFloat;". In contrast, in C, the "double" keyword is used before the variable name to declare a double variable. as in "double myDouble;".
• Typecasting: Typecasting can be used to change a float into a double or vice versa. For instance, you would type "double myDouble = (double) myFloat;" to change the float "myFloat" into a double. You would enter "float myFloat = (float) myDouble;" to change the double variable "myDouble" into a float. However, if you're converting from double to float, be aware that typecasting can reduce precision.
• Rounding Errors: Float and Double can experience rounding errors because there are only so many bits that can be used to represent a value. It is so that the computer can round the value to the closest representable value since some values cannot be precisely represented with a finite number of bits. Over time, these rounding errors could add up and cause unexpected behavior or inaccurate results.
• Literals: To define a literal as a float or double, use a suffix. For instance, "f" or "F" can be used to denote a float literal, and "d" or "D" can denote a double literal. As opposed to 14, which is a double literal, 3.14f is a float literal.
• Constants: For working with float and double values, C includes a number of predefined constants, including FLT_MAX, FLT_MIN, DBL_MAX, and DBL_MIN. The maximum and minimum values that can be stored in a float or double variable are represented by these constants.
• Overflow and underflow: An overflow or underflow error may occur if you attempt to store a value that is either too large or too small for a float or double variable. An underflow happens when the value is too small to be represented by the variable, whereas an overflow happens when the value is too large. Both outcomes could have an unexpected value or behavior as a result.