当前位置:网站首页>7-21 wrong questions involve knowledge points.
7-21 wrong questions involve knowledge points.
2022-04-23 18:02:00 【OceanKeeper1215】
1、 Permission is 765 The file of , The corresponding permission bit is marked as ?
Linux The permissions on files in are expressed as rwx.
When the permission mark indicates, the first bit indicates the file or directory , For documents - Express , The catalog uses d Express .
From the second to the last , Divide every three into a group , Represents the owner of the file , The same group and other users on the file Operation permission of .
The answer to this question is to first 765 Expressed as the corresponding binary number , obtain 111110101, Corresponding rwxrw-r-x. Add the first digit to represent the file . The final answer is :-rwxrw-r-x.
2、 If there are the following procedures
#include <stdio.h>
#define SUB( X,Y ) (X+1)*Y
main( )
{
int a=3,b=4;
printf( "%d\n" ,SUB( a++ ,b++ ) );
}
The output of the program after running is ? 16
i++ It means to use first i Value Then add it by yourself
++i It means to add... First Use it again i Value
The macro definition is just a simple replacement , perform SUB( a+ + ,b+ + ) =SUB( a+ + +1)*b+ +=16
3、
True value is -100101 The number of words is 8 In the machine of , Its complement form is (11011011).
The original code is :10100101( The word is 8 Machine , There are no eight bytes of data , Therefore, the symbol bit is followed by 0)
4、
One C Language program on a computer 32 Bit machine . Three variables are defined in the program x、y and z, among x and z by int type ,y by short type . When x=127,y=-9 when , Execute assignment statement z=x+y after ,x、y and z The values of
x=0000007FH,y=FFF7H,z=00000076H
C Integer data in the language is in the form of complement ,int by 32 position ,short by 16 position , so x、y Convert to hex 0000007FH、FFF7H. perform z=x+y when , because x yes int type ,y by short type , Short word length data needs to be converted into long word length data , be called “ Symbol extension ”. because y The sign bit of is 1, Therefore, in y Add before 16 individual 1, Can be y Rise to int type , Its hexadecimal form is FFFFFFF7H. Finally, add , namely 0000007FH +FFFFFFF7H=00000076H, The carry of the highest bit 1 Natural discard
5、 Listed below C In language constants , The wrong is ()
U Indicates that the constant is stored as an unsigned integer , amount to unsigned int, namely 1U amount to unsiged int 1; L Indicates that the constant is stored as a long integer , amount to long; F Indicates that the constant is stored in floating-point mode , amount to float
1.2e0.5 For the wrong expression ,e It should be followed by an integer .
'\72' Represents a legal character constant ,\ For escape characters , For octal ,ascii Code for 8*7 + 2= 58;58 This ASCII, namely ':' This character
6、
void main (void) {
int x;
x = printf(“I See, Sea in C”);
printf(“x=%d” , x);
}
When the program is finished x What is the value of ?
15
printf() The return value of is the number of characters printed , If an error occurs, a negative value is returned .
x To be an assignment 15.
版权声明
本文为[OceanKeeper1215]所创,转载请带上原文链接,感谢
https://yzsam.com/2022/04/202204230545105346.html
边栏推荐
- [UDS unified diagnostic service] (Supplement) v. detailed explanation of ECU bootloader development points (1)
- 解决报错max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
- Yolov4 pruning [with code]
- Timestamp to formatted date
- C#的随机数生成
- Fashion classification case based on keras
- Read excel, int digital time to time
- Eigen learning summary
- journal
- Summary of floating point double precision, single precision and half precision knowledge
猜你喜欢
Go的Gin框架学习
C1小笔记【任务训练篇二】
Anchor location - how to set the distance between the anchor and the top of the page. The anchor is located and offset from the top
ArcGIS license error -15 solution
开源按键组件Multi_Button的使用,含测试工程
2022江西储能技术展会,中国电池展,动力电池展,燃料电池展
Tell the truth of TS
[UDS unified diagnostic service] v. diagnostic application example: Flash bootloader
Calculation of fishing net road density
Operators in C language
随机推荐
Tell the truth of TS
Timestamp to formatted date
ES6
Build openstack platform
Welcome to the markdown editor
ArcGIS table to excel exceeds the upper limit, conversion failed
Map basemap Library
Vite configure proxy proxy to solve cross domain
Go's gin framework learning
In JS, t, = > Analysis of
读取excel,int 数字时间转时间
Error in created hook: "referenceerror:" promise "undefined“
Clion installation tutorial
Oil monkey website address
Selenium + phantom JS crack sliding verification 2
C language loop structure program
Selenium + webdriver + chrome realize Baidu to search for pictures
positioner
How to read literature
Laser slam theory and practice of dark blue College Chapter 3 laser radar distortion removal exercise