How memory is allocated for a variable declared outside vs inside main ()

Question

I noticed that when working with some large arrays (for example, it doubles 1000 per 1000) my program runs out of memory if I declare an array inside main (), but this never happens if I declare an array outside of main () even for large arrays . Can someone explain what the difference is?

Answer 1

When a variable is declared inside a function (in your case main), it is allocated on the stack, and if it is too large (for example, a large array), you will encounter a stack overflow .

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Answer 2

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Answer 3

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Answer 4

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Answer 5

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Answer 6

the stack size is about 2-3 M, and the heap size is associated with virtual memory. It can be very big. you can declare it as follows:static int num[1000][1000];