C Primer Plus reading notes chapter II

The title of this chapter is a C language overview, which is about some simple sample programs to understand and familiarize yourself with some of the basic features of C language.

This is the first piece of code in the book, knocking and looking for feelings. It is recommended to write code in a Linux environment.

PS: Daoteng Sublime text One afternoon, want to install a Sumblimeclang plug-in, the results directly to the sublime text collapse, anger for Atom, with a good.

#include <stdio.h>int main (void)/   * A simple C program */{    int num;     /* defined as a variable named num */    num = 1;     /* Assign value *    /printf ("I am a simple"); /* Use the printf () function */    printf ("computer.\n");    printf ("My favorite number is%d because it is first.\n", num);    return 0;}

The code is simple. The following 2.2-section example illustrates very detailed. Good for beginners to read again and again.

Attention:

1. #include不是C语言的语句, #符号表示这一行是在编译器接手前由C预处理器处理的语句.

2. Traditionally, the C language requires that a variable be declared at the beginning of a block of code, in which no other statement is allowed. Now C99 follows the C + + principle, allowing the declaration to be placed anywhere in the code. However, many compilers do not support the C99 rule.

3. Tips for making the program readable: 1. Select a meaningful variable name. 2. Use annotations. 3. Use a blank line to separate the concept of a function from multiple parts. 4. One line.

The third example code in the book is as follows

#include "stdio.h" Void Butler (void); /* Iso/ansi C function prototype */int main (void) {    printf ("I'll summon the butler funtion.\n");    Butler ();    printf ("Yes, bring me some tea and writeable cd-roms.\n");    return 0;} void Butler (void) {    printf ("You Rang, sir?\n");}

The C90 standard adds a prototype, which is a declarative form that tells the compiler that you are using a special function and indicating the properties of the function. C Standard Recommended function prototypes for all functions to be used.

Debugger methods: 1. Step-by-step tracking procedures. 2. Add additional printf () statements to key places. 3. Use the debugger.

After-school exercises are all about printf (), no difficulty.

To be Continued ...

C Primer Plus reading notes chapter II