C How do I change the value of a defined global variable in a local function?

Just modify it directly.

Global variables are visible globally, as well as within local functions.

If you're talking about the case where the arguments of a local function have the same name as a global variable, you need to use the monocular operator ::

For example, if the global variable is named temp, it should be written as: temp.

1. First, define a custom function that implements addition operations.

2. Next, define a custom function that implements multiplication.

3. Finally, the operation of the program is implemented in the main function.

4. Variables that are not enclosed in curly braces outside the function are called global variables, and the scope of the global variable starts from the position where the variable is defined and ends at the end of the file.

5. If multiple functions in a program have to process the same variable, you can define this variable as a global variable, for example, in this case, the custom function product and the main function both use global variables.

6. Run the program, and you can see that the global variable works on any function in the file that is located after the global variable definition.

Just manipulate this global variable, as long as there are no local variables with the same name as the function inside, you can boldly change it.

1.In general, it is enough to use it directly;

2.What if there is a variable with the same name as the global variable in this local function? Let's change the local variable to a different name;

3.If the global variable is in another file, add the extern keyword to the place where it is defined;

Just use it, global variables can't be used in local functions.

Global variables are generally only defined when defined, and initial values can be assigned when they are referenced.

You can use it directly, as long as it doesn't have the same name as a local variable

Define variables, don't put them in any function, including the main function, just do it.

Hello: It's good to define it outside of the main function and other functions, preferably at the top of the file.

Good luck!

1. First of all, we can define variables outside the function, which are global variables.

2. Local variables can be named the same as global variables.

3. But the priority is local variables.

4. But the life cycle of local variables is within the entire structure.

5. The global variable is released only at the end of the whole program.

6. We can also add modifiers to variables.

Of course, it's legal, but it can't be used indiscriminately, and if it's defined correctly, it must be used correctly, for example.

If you define (int

You can't use it as if it were char, so you'll have to look at the program you conjure up repeatedly to see if it's wrong.

As we all know, after a global variable is defined, the system allocates memory for the global variable and it can also be called by other modules via the extern keyword in C. This must be defined in the and files.

Global variables in C are mainly variables defined outside of all functions, which are valid during program execution, and can be referenced and assigned by any function.

For example, in the following segment, the variable m is a global variable defined outside the main function main(), which can be accessed by the function fun 1 or fun 2.

#include

int m;

int main()

void fun_1()

void fun_2()

Global variables,"The compilation unit of a program is the source program file, and a source file can contain one or more functions. Variables defined inside a function are local, while variables defined outside of a function are called external variables, and external variables are global variables (also known as full variables). Global variables can be shared by other functions in this file.

It is valid from the point where the variable is defined to the end of the source file. "The purpose of setting global variables is to increase the channels for data connections between functions.

The variables that are defined outside the function body are called global variables, and to define global variables, you just need to define the variables in.

All functions are external.

Note that a global variable only defines bits for it.

The following functions can be seen.

#include

void f1();

void f2();

int y=100;

int main()

int x;

void f1()

void f2()