ateixt()

/*
the atexit() function is a registered termination handler, which is a function registered with this function and runs only when the program terminates.
the essence of atexiti() is simliar to the callback function.
*/ (719) 227-8872

dup() && dup2()

/**********************************dup()******************************************/
/*
#include <unistd.h>
int dup(int oldfd); 450-308-6269

random numbers

/******************************************************************************

Random numbers are completely random and have no regularity, which is an ideal state.
The randpm number we often said are actually pseudo random, which is regularity under a certain conditions.

******************************************************************************/

7035022936

(256) 404-6745

/*********************************test1 : time()*****************************************/
/*
time() returns the time as the number of seconds since the Epoch,
1970-01-01 00:00:00 +0000 (UTC). Mandingan

File operation

There are many kinds of document,such as directory files, text files,each file must be parsed in the way it was written

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8732547388

1.软件测试的目的是_尽可能多地发现程序中的错误_,通常可分为白盒测试和黑盒测试。白盒测试根据程序的_内部逻辑_来设计测试用例,黑盒测试根据软件规格说明来设计测试用例。 阅读详细 »

嵌入式程序设计师考试题目(5)

1.下列关于D/A变换器接口的描述,不正确的是(C)

A.它是嵌入式微机系统与外部模块控制对象的重要控制接口

B.它通常由模拟开关、权电阻电路、缓冲电路组成

C.它也可以把外界的模拟量变成数字量

D.它输出的模拟量可以是电流也可以是电压

解析:D/A中,D指digital,A指analog。D/A只能把digital转换为analog。A/D可以把模拟量转为数字量 阅读详细 »

ground elder

  1. 在指令系统的各种寻址方式中,获取操作数最快的方式是(立即寻址)。若操作数的地址包含在指令中,则属于(直接寻址)方式。

(331) 814-7661