C基础讲义2018修订版1

1、C 语言概述 ....................................................................................................................................2

1.2.5 学习 C 语言的常见困惑 ............................................................................................5

1.3 第一个 C 语言程序：HelloWorld ........................................................................................5

1.3.1 编写 C 语言代码：hello.c..........................................................................................5

1.3.2 通过 gcc 编译 C 代码 .................................................................................................6

1.3.3 代码分析...................................................................................................................11

1.4 system 函数 ..........................................................................................................................12

1.4.1 system 函数的使用 ...................................................................................................12

1.5 C 语言编译过程 ..................................................................................................................13

1.5.1 C 程序编译步骤 .......................................................................................................13

1.5.2 gcc 编译过程.............................................................................................................13

1.7.1 VS 中 C 语言嵌套汇编代码(了解)..........................................................................17

1.7.2 VS 反汇编 .................................................................................................................17

1.8 集成开发环境 IDE ..............................................................................................................19

2. 数据类型........................................................................................................................................21

2.1 常量与变量..........................................................................................................................21

2.1.1 关键字.......................................................................................................................21

2.1.2 数据类型...................................................................................................................22

2.1.3 常量...........................................................................................................................22

2.2.4 有符号数和无符号数区别.......................................................................................27

2.3 sizeof 关键字........................................................................................................................28

2.4 字符型：char .......................................................................................................................29

2.4.1 字符变量的定义和输出...........................................................................................29

2.4.2 字符变量的输入.......................................................................................................30

2.4.2 ASCII 对照表............................................................................................................30

2.4.3 转义字符...................................................................................................................31

2.5 实型(浮点型)：float、double .............................................................................................32

2.6 进制......................................................................................................................................33

2.7.3 补码...........................................................................................................................38

2.7.4 补码的意义...............................................................................................................39

2.7.5 数值溢出...................................................................................................................40

2.8 类型限定符 ..........................................................................................................................41

2.9 字符串格式化输出和输入 ..................................................................................................42

2.9.1 字符串常量...............................................................................................................42

2.9.2 printf 函数和 putchar 函数 .......................................................................................42

2.9.3 scanf 函数与 getchar 函数 ........................................................................................43

3. 运算符与表达式............................................................................................................................44

3.1 常用运算符分类..................................................................................................................44

4. 程序流程结构................................................................................................................................49

4.1 概述......................................................................................................................................49

4.2 选择结构..............................................................................................................................49

4.2.1 if 语句........................................................................................................................49

4.2.2 if…else 语句..............................................................................................................50

4.3.1 break 语句 .................................................................................................................55

4.3.2 continue 语句 ............................................................................................................56

4.3.3 goto 语句(无条件跳转，尽量少用) ........................................................................57

5. 数组和字符串................................................................................................................................57

5.1 概述......................................................................................................................................57

5.2 一维数组..............................................................................................................................58

5.2.1 一维数组的定义和使用...........................................................................................58

5.2.2 一维数组的初始化...................................................................................................59

5.2.3 数组名.......................................................................................................................59

5.2.4 强化训练...................................................................................................................60

5.3 二维数组 ..............................................................................................................................61

5.3.1 二维数组的定义和使用...........................................................................................61

5.3.2 二维数组的初始化...................................................................................................63

5.5.3 字符串的输入输出...................................................................................................67

5.5.4 强化训练：字符串追加...........................................................................................70

6. 函数................................................................................................................................................70

6.1 概述......................................................................................................................................71

6.1.1 函数分类...................................................................................................................71

6.1.2 函数的作用...............................................................................................................71

6.1.3 函数的调用：产生随机数.......................................................................................72

6.2 函数的定义..........................................................................................................................73

6.2.1 函数定义格式...........................................................................................................73

6.2.2 函数名字、形参、函数体、返回值.......................................................................74

6.4 函数的声明..........................................................................................................................80

6.5 main 函数与 exit 函数 .........................................................................................................81

6.6 多文件(分文件)编程 ...........................................................................................................81

6.6.1 分文件编程...............................................................................................................81

6.6.2 防止头文件重复包含...............................................................................................82

7. 指针................................................................................................................................................82

7.1 概述......................................................................................................................................83

7.1.1 内存...........................................................................................................................83

7.1.2 物理存储器和存储地址空间...................................................................................83

7.1.3 内存地址...................................................................................................................83

7.2 指针基础知识......................................................................................................................85

7.2.1 指针变量的定义和使用...........................................................................................85

7.2.2 通过指针间接修改变量的值...................................................................................85

7.2.3 指针大小...................................................................................................................85

7.2.4 野指针和空指针.......................................................................................................86

7.2.5 万能指针 void * ........................................................................................................86

7.2.6 const 修饰的指针变量..............................................................................................87

7.3 指针和数组..........................................................................................................................87

7.3.1 数组名.......................................................................................................................87

7.3.2 指针操作数组元素...................................................................................................87

7.3.3 指针加减运算...........................................................................................................88

7.3.4 指针数组...................................................................................................................90

7.7.1 字符指针...................................................................................................................93

7.7.2 字符指针做函数参数...............................................................................................93

7.7.3 const 修饰的指针变量..............................................................................................94

7.7.4 指针数组做为 main 函数的形参 .............................................................................94

7.7.5 项目开发常用字符串应用模型...............................................................................95

7.7.8 字符串处理函数.......................................................................................................99

7.8 指针小结............................................................................................................................104

8. 内存管理......................................................................................................................................105

8.1 作用域................................................................................................................................105

8.1.1 局部变量.................................................................................................................105

8.2 内存布局............................................................................................................................108

8.2.1 内存分区.................................................................................................................108

8.2.2 存储类型总结.........................................................................................................110

8.2.3 内存操作函数 .........................................................................................................112

8.2.4 堆区内存分配和释放.............................................................................................113

8.3 内存分区代码分析............................................................................................................114

9. 复合类型(自定义类型) ...............................................................................................................117

9.1 结构体................................................................................................................................117

9.1.1 概述.........................................................................................................................117

9.1.2 结构体变量的定义和初始化.................................................................................117