Review the C language Parsing tutorial (i)

Recently went to the library to learn C language books, feel by < Mei >al Kelley and Ira Pohl-Mazhi translation of the "C Language Analysis Tutorial" translated very good, especially the C language learning method (of course, I still compare the suggestion to learn the two languages and then do a good tour), In the process of learning C language, interspersed with c++!

In the C language of the road, I still want to work hard is!

1. Programs that do not contain header files can also be run!

int Main () {    int a=3, b=4;     return 0 ;}

2. If a and B are variables of type int, where one or two are negative, the value of A/b is system-dependent and is determined by the system.

Variables of type 3.float are usually added to the right of the assignment statement with F.

A constant of 4.long double is added to L.

5. When the constant is a double type, the variable is of type float, so there is no problem.

Note: Floating-point types can be freely mixed in expressions and assignments.

    float  x, y;    X=1.0// Note: This sentence and the following sentence are missing F    y=2.0;

6. The Division of floating-point numbers is the same as people's imagination, according to normal division.

Example: 7.0/2.0=3.5

7. In a floating-point expression, 0 is not allowed to divide, otherwise a value that is not a number may be generated.

Note: This can be run in dev, displaying values that are not numbers, which, under vc++6.0, will give an error and the executable program cannot be generated.

header files such as stdio.h in a 8.UNIX system are typically in/user/include

9. #define can appear anywhere in the program, affecting only those rows that follow it in the file.

Note: Usually after # include, the changed identifiers are written in uppercase

10. Formatting control in the printf () function

Floating point number of%e scientific counting method

%g in E-format or F-format, takes a shorter one

11. The address of a variable is the address stored in the variable memory. (Here's a question: What's the difference between this memory and storage?) ）

12.SCANF () function format control character

LF stands for double

LF represents a long double

13. In the traditional C language, long float is synonymous with float, but in Ansic C, there is no long float.

Note: Do not consider this article now, understand can.

14.

 while (scanf ("%f", &x) = =1);

Indicates that if successful, convert the user input character to float type to save X, success is true, failure returns 0, no re-use return-1

In 15.UnIx, a carriage return followed by Ctrl+d is a typical end-of-file flag.

16. Note: In an interactive environment, it is not an error for a program to use a dead loop!

17. In Unix, common CTRL + C interrupts the program.

In 18.UNIX, the command ls>temp is to write the contents of the previous output to the screen to a file, which is referred to as redirection.

C++

The 1.c++ I/O library is iostream.h

2.

count<<"hello,world! "<<endl;

Count represents the screen

<< is putting a string into the output stream

Endl for refreshing output and moving to a new line

In the 3.c++ program, return 0 can be ignored;

Note: This statement is inserted because of its implication.

4. Greatest common Divisor

 while (n!=0)    {        R=m%N;        M=N;        n=r;    }     // the final output of M is greatest common divisor

5.cin is usually the standard input stream associated with the keyboard.

cin>>m>>n;

6. Note:

1 Finder = 6 feet

1 feet = 12 inches

1 yards = 36 inches

Review the C language Parsing tutorial (i)