章节要点（Chapter key）.docVIP

章节要点（Chapter key） Chapter 1 C Language Overview 1.1 main function (*) 1, the main function is the entry of a program. A program starts with the main function and ends with the main function 2, a program can only have a main function, the location is not limited 3, the basic unit of the C program is the function, that is, a C program is made up of multiple functions. 4, understand that the function is called 1.2, write the main idea of the program 1 most programs are composed of input processing output 2, the program needs to open up space before memory - both defining variables 3, the role of header files - statements that contain system definitions and user-defined functions 4, C language size distinction, statements end with a semicolon, the use of annotations Common shortcut keys on 1.3 TC 1, *.c, *.obj, *.exe 2, Alt + F5, Ctrl + F9, F2, Alt+X, Ctrl + break, /Ctrl+F2, end the dead loop (*) 3, run, compile, connect, view the running results, save, help and other shortcut keys 1.4 algorithm thinking Program = data structure + algorithm Structured programming - order, selection, loop The third chapter, data types, operators, and expressions 3.1, data type 1, why do you have data types? 2, the data type of this chapter Int, short, long Signed, unsigned, Float, double, long, double 3. What is a constant and what is a variable?. Attention - definition of symbolic constants #define PI 3.1415926 The role of symbolic constants - to improve program maintainability and readability Note - after the variable definition, type name variable 1, variable 2.; You must have the concept of memory in your mind. 4, C language naming rules 3.2 integers 1, integer constant form and shaping variable in memory form N decimal conversion, decimal, octal and sixteen hexadecimal form of constant Output form%d,%o,%x,%u 2, the scope of the integer problem, overflow problem (*) 3.3 floating point numbers 1, the constant form of floating point numbers and variable definitions of floating point nu