(1) main function is the name of the main function, each of the C source must have one and only one main function (main () function)
(2) in front of the main int integer type specifier, int main () is a front is an integer function of the type
(3) return 0; action: If the normal operating procedures, before the end of the function value as an integer of 0; if abnormal execution, the program will be interrupted, return 0 ;, function value at this time is not performed non-zero integer
(4) printf () function is the function to be output to the display contents of the display. printf () function is a function defined by a standard system that is declared in the header file stdio.h in need #include command to include it as #include <stdio.h>
(. 5) #include files referred to contain command, .h file called extension headers
(6) single and double quotes is a difference
(7) scanf () function of the input, the printf () is a function of an output
(8) of the main function of two parts: Description section or part of a declaration portion; another part of the operative part, each of description, each statement must end with a semicolon, the pre-command, function header and braces "}" after the semicolon does not
