Several major misunderstandings of the C language strlen() function (must read the exam, so as not to step on the pit)

The role of the strlen() function: count the length         of a given string

Function: Count the number of characters in the string str, excluding '\0'

That is to say, when the character  '\0'            is encountered , the strlen() function will end (\0 is not included in the length)

Note: The difference between 0 and '0'              The value of '0' is 48,

                                        The value of '\0' is 0, and the end of encountering '\0' is the end of encountering 0

                                        But it's not the end of case '0'!

Example 1: 

#include<stdio.h> 
#include<string.h> 
int main() {
	char s[]="hebeisheng\0\n";
	printf("%d",strlen(s));
	return 0;
}

  The value of '\0' is 0, and the end of encountering '\0' is the end of encountering 0

So only the length before \0 is counted

 Example 2: 

 If we add '\0' to the string 

#include<stdio.h> 
#include<string.h> 
int main() {
	char s[]="hebeisheng'\0'\n";
	printf("%d",strlen(s));
	return 0;
}

The final result is 11, just add the single quotation mark in front of '\0', encountering \0 will still end the strlen function

Example 3: 

 When using the strlen function: you should pay attention to escape characters, a set of escape characters counts as a length

Attachment: escape character table