How to use global variables in C language

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1. All variables defined outside the function are called global variables, and their default functional domains are valid from the location of the defined variable to the end of the source file.

2. If you need to use global variables, it is best to define them at the top of the file, so that all functions in the file can be used directly.

Example

# include void func1 () {x + = 10; y + = 20; printf ("function:% s x =% d y =% d\ n", _ _ FUNCTION__,x,y);} int x = 10 × int y = 20; void func2 () {x + = 10; y + = 20; printf ("function:% s x =% d y =% d\ n", _ _ FUNCTION__,x,y) } int main () {func1 (); func2 (); printf ("function:% s x =% d y =% d\ n", _ _ FUNCTION__,x,y); return 0;} / * output: main.cpp: In function 'void func1 ()': main.cpp:6:5: error:'x 'was not declared in this scope 6 | x + = 10 | | ^ main.cpp:7:2: error:'y' was not declared in this scope 7 | y + = 20; | ^ * / above is about the article "how to use global variables in c language". I believe you all have some understanding. I hope the content shared by the editor will be helpful to you. If you want to know more about it, please follow the industry information channel.