Preface ：Hello！ Hello everyone , I am a @ Typing code every day ; Thank you for your support ！

      Until today , About C The content of the initial stage of language , We'll finish reviewing ; For the preliminary content, my focus is to let you know in the form of exercises . Next, let's review C The advanced part of language , Of course, I will continue to update some data structures . For advanced, most of them are Use of the pointer and Memory understanding , So we must learn the content of the pointer well , Or it'll be big in the back ！ I will also talk about the advanced part in detail , Including some concepts and definitions 、 And the form of data stored in memory ！ Today we will conclude with an example C Elementary language learning , I hope this example will make you gain something .

subject ：

analysis ：

This problem is obviously to use Flipping , How to flip ？ How many times ？ This may be difficult to grasp ; The method of this problem is similar to three-step translation and forwarding , We used to be in a rotating array ( Left and right ) Mentioned in , Interested friends can learn ： Rotated array ( Left and right )

First step ： First, we definitely need to get this string , use scanf obtain ？ Of course not ,scanf Space encountered (" ") It will end , So here we need to use gets To receive the entire string , We directly gets( Array name ) perhaps gets_s( Array name , Array size ), Both are OK , The latter is relatively safer ！ Pay attention to the header file <string.h>

The second step ： We encapsulate a Rotation function reserve, Put the whole string in reverse order first ; This is very simple , We've met a lot of this before , I won't repeat .

The third step ： We need to reverse the order of each word , How to control ？ such as ： Let's take the test cases given by the topic to analyze ：I  like  beijing.

First of all, we can't move arr, need arr This first address controls printing ！

So you need to define two pointers start and end,char* start = arr,char* end = start, We need to write two loops , A control start The pointer , A control end The pointer ;

as long as end The pointer did not encounter a space (" ") perhaps \0 let end++; When you jump out of the loop , Must be end Space encountered (" ") perhaps \0 了 , Let's ignore the others , First call the rotation function reserve, Rotate the previous word ; Then analyze , What kind of situation ：

Case one ： If you encounter spaces (" "), It means that the word is over , You need to skip this Space (" "), let start =end+1,start Just remember the starting position of the next word , Then continue to end++, Repeat this operation ！

The second case ： If you meet \0, Description to the end of the string , At this point, put end Assign a value to start,strat=end=\0, So you can exit the loop .

Step four ： Let's just print it .

Code implementation ：

To test ：

summary ：

This blog is a little less , I didn't think of it , But I think this question is quite classic , I hope you guys have something to gain , Thank you for your support ！ Next time we will learn the advanced content . Learning together ！ Progress together ！