C# language uses ** float** variable type to store real number values in floating point (negative and positive numbers that contain a fractional part). The C# compiler will allocate 32 bits (4 bytes) to store values of type float. A float variable type can store values with a precision of six or seven decimals in the interval of

*and*

**3.4E-38***.*

**3.4E+38**The C# language keeps the value on a *mantissa* of 23 bits (which contains the fractional part) and an exponent of 8 bits (which contains the power with which the number is multiplied) and a single bit of sign (which tells the compiler if the value is positive or negative). In other words, if a variable contains the value * 3.4E+38*, the sign bit will be

*, which indicates a positive number, the 23 bits mantissa will contain a binary representation of number 3.4, and the 8 bit exponent will contain a binary representation of 10*

**0**^{38}

Additional Information

**scientific notation.**This system allows to represent any number utilizing a single digit to the left of the point, an unlimited number of digits to the right of the point, and an exponent using a power of 10. When you calculate the real value of the number, multiply the number (mantissa) with the value of 10 to the

*x*power (where x represents the exponent). For instance, number 3.1415967E+7 equals to 31415967.0, or 3.1415967 * 10

^{7}

*.*

If you want a numeric real literal to be treated as *float*, use the suffix f or F, for example:

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float myFloatVariable = 157.39F; |

Without the suffix f, the number is treated as a double and generates a compiler error.

*The concepts explained in this lesson are also shown visually as part of the following video:*

**EXERCISES**

**1.** Write an expression that calculates the **area of a trapezoid** by given sides **a**, **b** and height **h**.

Solution

Guidelines: The formula for

**trapezoid surface**is: S = (a + b) * h / 2.

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static void Main(string[] args) { float a = 2; float b = 3; float h = 1; Console.WriteLine("S={0}", (a + b) / (2 * h)); Console.Read(); } |

Tags: float variable, variable types, variables