当前位置:网站首页>The third level of C language punch in
The third level of C language punch in
2022-07-06 02:16:00 【HTTPS 443୧⍤⃝】
One 、 Cast expression
form :( Type name ) expression
function : Converts the value of an expression to the specified data type
(double) 1/2 The value of is 0.5 ( As mentioned in the last section 1/2 It's two integers Should the 0 Because there is a double, The value is decimal 0.5, amount to (double)1/2 Equivalent to 1.0/2)
The level of cast takes precedence over division
This table describes the transformation rules more vividly
Two 、 Assignment expression
form : Variable name = expression
On the left is a variable name , Get the value of an expression on the right , Assign the value of the expression to a variable , Its combination is
From right to left , Its priority is only higher than comma operator . The value of the assignment expression is the new value obtained by the leftmost variable .
Simply put, it's the left A variable , On the right is an equation . such as :a=2+7/3
(1) Compound assignment expression
such as n+=1 Equivalent to n=n+1
n*=m+3 Equivalent to n=n*(m+3)
Yes : = += -= /= %= &= ^= wait associativity : From right to left
(2) Type conversion in assignment operation
int x; x=6.5; //x Integers 6, Here is a transformation , Convert to be consistent with the type of variable double y; y=6; //y by 6.0, Here is a transformation , Convert to be consistent with the type of variable
3、 ... and 、 Auto increment and auto decrement operator
Self adding 、 The subtraction operator is ++ and --. Self adding ( reduce ) Operator in front , First increase ( reduce ) After use ; Self adding ( reduce ) Operator after , Use first and then increase ( reduce ). The combination direction of operators is from right to left ,-k++ Equivalent to -(k--).
Self adding ( reduce ) There are often two operations in the operation : Calculate the value of the expression and the value of the variable .
set up k=3, Calculate the value of the following assignment expression and calculate the value of the variable
expression x Value k Value The value of the assignment expression x=k++ 3 4 3 x=++k 4 4 4 x=k-- 3 2 3 x=--k 2 2 2 As can be seen from the table :++ Must make k increase 1,-- Must make k reduce 1, Because it is an assignment expression , therefore x The value of is interlinked with the value of the expression
Four 、 Comma operators and comma expressions
form : expression 1, expression 2,....., expression n
Combination direction : From left to right
Operational rules : So let's evaluate the expression 1 Value , And then evaluate the expression 2 Value , And then calculate the expression 3 Value ,..... Finally, calculate the expression n Value , expression n The value of is the value of the entire comma expression
The comma expression has the lowest priority , Lower than assignment
int x=8,y=12,z=14 x++,y=z++,z=++x; y=x%z--; // Last x=10 y=0,z=9
answer :
The original x=8 You can see that from the top Yes x++ Add a ,++x Once again, , Total increase 2 Time , Namely 8+2=10
The original y=12 y=X%z-- here x=10 z=10 because z=++x ,z-- Is the suffix with the previous value 10 To participate in the calculation , therefore 10%10=0 ,y Is equal to 0
The original z=14 First, y=z++ ,z=15 also z=++x ,z be equal to 10, Last z-- Say with z=9
Answer of last issue :
#include<stdio.h>
void main()
{
double a,b,c; // Define three real numbers
double sum,aver; //sum Storage and ,aver Store the average
scanf("%lf%lf%lf",&a,&b,&c); // Input 3 A real number
sum=a+b+c; // Calculation 3 Sum of numbers
aver=(a+b+c)/3; // Calculation 3 The average of the numbers
getchar();
getchar();
}
This assignment
1. Enter the of the triangle 3 Strip side length , Find the area of three triangles ( Query the formula on the Internet , I will use the square function sqrt, File header is required math.h)
2. Input 2 Number , In exchange for 2 The value of the number
for example : x=2 ,y=3 After exchanging x=3,y=2
边栏推荐
- Visualstudio2019 compilation configuration lastools-v2.0.0 under win10 system
- Derivation of Biot Savart law in College Physics
- FTP server, ssh server (super brief)
- 一题多解,ASP.NET Core应用启动初始化的N种方案[上篇]
- Grabbing and sorting out external articles -- status bar [4]
- 【MySQL 15】Could not increase number of max_open_files to more than 10000 (request: 65535)
- [community personas] exclusive interview with Ma Longwei: the wheel is not easy to use, so make it yourself!
- [solution] every time idea starts, it will build project
- Paper notes: graph neural network gat
- Use image components to slide through photo albums and mobile phone photo album pages
猜你喜欢
Know MySQL database
SPI communication protocol
How does redis implement multiple zones?
2022 PMP project management examination agile knowledge points (8)
Grabbing and sorting out external articles -- status bar [4]
Leetcode3. Implement strstr()
Card 4G industrial router charging pile intelligent cabinet private network video monitoring 4G to Ethernet to WiFi wired network speed test software and hardware customization
Visualstudio2019 compilation configuration lastools-v2.0.0 under win10 system
Leetcode3, implémenter strstr ()
leetcode3、實現 strStr()
随机推荐
一题多解,ASP.NET Core应用启动初始化的N种方案[上篇]
PHP campus movie website system for computer graduation design
Redis string type
Text editing VIM operation, file upload
Leetcode sum of two numbers
更改对象属性的方法
The ECU of 21 Audi q5l 45tfsi brushes is upgraded to master special adjustment, and the horsepower is safely and stably increased to 305 horsepower
Genius storage uses documents, a browser caching tool
VIM usage guide
模板_快速排序_双指针
Apicloud openframe realizes the transfer and return of parameters to the previous page - basic improvement
Minecraft 1.18.1, 1.18.2 module development 22 Sniper rifle
Blue Bridge Cup embedded_ STM32_ New project file_ Explain in detail
2 power view
Gbase 8C database upgrade error
Selenium waiting mode
02. Go language development environment configuration
SPI communication protocol
[width first search] Ji Suan Ke: Suan tou Jun goes home (BFS with conditions)
Online reservation system of sports venues based on PHP