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书籍整理内容：

最近在看C primer plus（加深巩固自己的C语言技巧，为以后学习C++打个基础）。 里面知识针对自己以后要查的点整理出来。 使用工具：visual studio 2013 ：https://blog.csdn.net/answerMack/article/details/103766020 ：https://blog.csdn.net/answerMack/article/details/103805900 ：https://blog.csdn.net/answerMack/article/details/103855794 ：https://blog.csdn.net/answerMack/article/details/103870182 https://blog.csdn.net/answerMack/article/details/103891048 https://blog.csdn.net/answerMack/article/details/103953376 https://blog.csdn.net/answerMack/article/details/103978471 ：https://blog.csdn.net/answerMack/article/details/104114028 ：https://blog.csdn.net/answerMack/article/details/105222269

本章主要讲解概念、基本都是函数的文字讲解。注意一下就好，易困！！

作用域

作用域描述程序中可访问标识符的区域。

（1）块作用域： （2）函数作用域 （3）函数原型作用域 （4）文件作用域

（6）翻译单元和文件

链接

c变量的属性：外部链接、内部链接、无链接

存储期

存储类别

自动变量

寄存器变量

块作用域静态变量

外部链接静态变量

定义变量、声明变量

内部链接静态变量

多文件

存储类别说明符

auto

register static extern _Thread_local typedef 例子：

// parta.c --- various storage classes// compile with partb.c#include 
   
    void report_count();void accumulate(int k);int count = 0;       // file scope, external linkageint main(void){
   	int value;       // automatic variable	register int i;  // register variable	printf_s("Enter a positive integer (0 to quit): ");	while (scanf_s("%d", &value) == 1 && value > 0)	{
   		++count;     // use file scope variable		for (i = value; i >= 0; i--)			accumulate(i);		printf_s("Enter a positive integer (0 to quit): ");	}	report_count();	return 0;}void report_count(){
   	printf_s("Loop executed %d times\n", count);}
   

// partb.c -- rest of the program// compile with parta.c#include 
   
    extern int count;       // reference declaration, external linkagestatic int total = 0;   // static definition, internal linkagevoid accumulate(int k); // prototypevoid accumulate(int k)  // k has block scope, no linkage{
   	static int subtotal = 0;  // static, no linkage	if (k <= 0)	{
   		printf_s("loop cycle: %d\n", count);		printf_s("subtotal: %d; total: %d\n", subtotal, total);		subtotal = 0;	}	else	{
   		subtotal += k;		total += k;	}}
   

存储类别和函数

随机数函数和静态变量

掷骰子

分配内存：malloc()和free()

3种创建数组的方法

/* dyn_arr.c -- dynamically allocated array */#include 
   
    #include 
    
      /* for malloc(), free() */int main(void){
   	double * ptd;	int max;	int number;	int i = 0;	puts("What is the maximum number of type double entries?");	if (scanf_s("%d", &max) != 1)	{
   		puts("Number not correctly entered -- bye.");		exit(EXIT_FAILURE);	}	ptd = (double *)malloc(max * sizeof(double));	if (ptd == NULL)	{
   		puts("Memory allocation failed. Goodbye.");		exit(EXIT_FAILURE);	}	/* ptd now points to an array of max elements */	puts("Enter the values (q to quit):");	while (i < max && scanf_s("%lf", &ptd[i]) == 1)		++i;	printf_s("Here are your %d entries:\n", number = i);	for (i = 0; i < number; i++)	{
   		printf_s("%7.2f ", ptd[i]);		if (i % 7 == 6)			putchar('\n');	}	if (i % 7 != 0)		putchar('\n');	puts("Done.");	free(ptd);	return 0;}
    
   

动态分配内存：

free()的重要性

calloc函数

动态内存分配和变长数组

动态内存分配和存储类别

#include 
   
    #include 
    
     #include 
     
      int static_store = 30;const char * pcg = "String Literal";int main(){
   	int auto_store = 40;	char auto_string[] = "Auto char Array";	int * pi;	char * pcl;	pi = (int *)malloc(sizeof(int));	*pi = 35;	pcl = (char *)malloc(strlen("Dynamic String") + 1);	strcpy_s(pcl, strlen("Dynamic String")+1,"Dynamic String");	printf_s("static_store: %d at %p\n", static_store, &static_store);	printf_s("  auto_store: %d at %p\n", auto_store, &auto_store);	printf_s("         *pi: %d at %p\n", *pi, pi);	printf_s("  %s at %p\n", pcg, pcg);	printf_s(" %s at %p\n", auto_string, auto_string);	printf_s("  %s at %p\n", pcl, pcl);	printf_s("   %s at %p\n", "Quoted String", "Quoted String");	free(pi);	free(pcl);	return 0;}
     
    
   

ANSI C类型限定符

const、volatile、restrict、_Atomic+stdatomic.h库文件

const（第4章、第10章）

指针和形参声明中使用const

volatile类型限定符

restrict类型限定符

_Atomic类型限定符

并行程序：

旧关键字的新位置

关键概念

本章小结

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2020-04-08

大连

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