C++ 如何在函数内部声明全局变量？
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How to declare global variable inside function?
提问by user3137147
I have problem creating global variable inside function, this is simple example:
我在函数内部创建全局变量时遇到问题，这是一个简单的例子：
int main{
int global_variable; //how to make that
}
This is exactly what I want to do:
这正是我想要做的：
int global_variable;
int main{
// but I wish to initialize global variable in main function
}
回答by Joseph Mansfield
You have two problems:
你有两个问题：
mainis not a loop. It's a function.Your function syntax is wrong. You need to have parentheses after the function name. Either of these are valid syntaxes for
main:int main() { } int main(int argv, const char* argv[]) { }
main不是循环。这是一个函数。您的函数语法错误。您需要在函数名称后加上括号。这些中的任何一个都是以下的有效语法
main：int main() { } int main(int argv, const char* argv[]) { }
Then, you can declare a local variable inside mainlike so:
然后，您可以在内部声明一个局部变量，main如下所示：
int main() {
int local_variable = 0;
}
or assign to a global variable like so:
或分配给一个全局变量，如下所示：
int global_variable;
int main() {
global_variable = 0;
}
回答by sasha.sochka
There is no way to declareit the way you want. And that's it.
没有办法按照你想要的方式声明它。就是这样。
But:
但：
- First, if you want you can declare it before the
mainbody but assign a value to it insidemain. Look Paul's answer for that - Second, actually there is no advantage of declaring variables the way you want. They are globaland that means they should be declared in the globalscope and no other places.
- 首先，如果你愿意，你可以在
mainbody之前声明它，但在main. 看看保罗对此的回答 - 其次，实际上按照您想要的方式声明变量没有任何优势。它们是全局的，这意味着它们应该在全局范围内而不是在其他地方声明。
回答by Boldijar Paul
int global_variable;
int main()
{
global_variable=3; // look you assigned your value.
}
回答by General Chaos
well... its indirectly possible by declaring pointers global, and later assigning local variables to them, but sometimes it may lead to situations where pointed variable is unaccessible .
嗯……通过声明全局指针，然后将局部变量分配给它们，间接可能是可行的，但有时可能会导致无法访问指向变量的情况。
