c-standard-library | 易学教程

Why do some built-in Python functions only have pass?

阅读更多关于 Why do some built-in Python functions only have pass?

I wanted to see how a math.py function was implemented, but when I opened the file in PyCharm I found that all the functions are empty and there is a simple pass . For example: def ceil(x): # real signature unknown; restored from __doc__ """ ceil(x) Return the ceiling of x as a float. This is the smallest integral value >= x. """ pass I guess it is because the functions being used are actually from the C standard library. How does it work? PyCharm is lying to you. The source code you're looking at is a fake that PyCharm has created. PyCharm knows what functions should be there, and it can

what is difference between fgetpos/fsetpos and ftell/fseek

阅读更多关于 what is difference between fgetpos/fsetpos and ftell/fseek

问题 What's the difference between using the functions fgetpos() and fsetpos() and using the functions ftell() and fseek() to get and set a position in a file? What are fgetpos() and fsetpos() good for? Why would they be used instead of ftell() and fseek() ? 回答1: None of the above answers are correct - in fact if you use fsetpos interchangeably with fseek you could introduce a security flaw (https://www.securecoding.cert.org/confluence/pages/viewpage.action?pageId=20087255). The reason is that the

What is the difference between getch() and getchar()?

阅读更多关于 What is the difference between getch() and getchar()?

问题 What is the exact difference between the getch and getchar functions? 回答1: getchar() is a standard function that gets a character from the stdin. getch() is non-standard. It gets a character from the keyboard (which may be different from stdin) and does not echo it. 回答2: The Standard C function is is getchar() , declared in <stdio.h> . It has existed basically since the dawn of time. It reads one character from standard input ( stdin ), which is typically the user's keyboard, unless it has

Why do some built-in Python functions only have pass?

阅读更多关于 Why do some built-in Python functions only have pass?

问题 I wanted to see how a math.py function was implemented, but when I opened the file in PyCharm I found that all the functions are empty and there is a simple pass . For example: def ceil(x): # real signature unknown; restored from __doc__ \"\"\" ceil(x) Return the ceiling of x as a float. This is the smallest integral value >= x. \"\"\" pass I guess it is because the functions being used are actually from the C standard library. How does it work? 回答1: PyCharm is lying to you. The source code

Why does pow(n,2) return 24 when n=5, with my compiler and OS?

阅读更多关于 Why does pow(n,2) return 24 when n=5, with my compiler and OS?

问题 #include <stdio.h> #include <stdlib.h> #include <math.h> int main() { int n,i,ele; n=5; ele=pow(n,2); printf(\"%d\",ele); return 0; } The output is 24 . I\'m using GNU/GCC in Code::Blocks. What is happening? I know the pow function returns a double , but 25 fits an int type so why does this code print a 24 instead of a 25 ? If n=4; n=6; n=3; n=2; the code works, but with the five it doesn\'t. 回答1: Here is what may be happening here. You should be able to confirm this by looking at your