In C language, e is a scientific symbol. Scientific counting method is very suitable for representing very large or very small numbers, because it can be simplified by exponential method and can better describe the accuracy of numbers. In c language, e is used to represent scientific notation. For example, 23e-4 represents 23 times 10 to the negative fourth power, that is, 0.000 123.

In addition to scientific notation, e is also a very common mathematical constant in C language, which represents the base of natural logarithm. Natural logarithm is widely used in mathematics, so it is often used in C language. For example, in computer science, many algorithms need to use natural logarithm, and e is the most important constant in this application.

In addition, e is also used to indicate some special events or errors in the program. Taking C language as an example, the program may encounter the error of dividing by zero when it is running. At this time, C language will return a special E value, indicating that an error has occurred; In addition, e can also be used to indicate the end of the file, indicating that the program has read the last bit of the file at this time. Therefore, e is not only a number or mathematical constant in C language, but also has rich semantics and significance.