struct를 초기화 하는 3가지 방법

1. 

#include <iostream>

int main()
{
    struct MyStruct
    {
		int x;
		int y;
    };

	MyStruct not_init_pos; // 초기화 하지 않음
	std::cout << "not init_pos x: " << not_init_pos.x << std::endl;
	std::cout << "not init_pos y: " << not_init_pos.y << std::endl;
	MyStruct init_pos = {}; // 모든 멤버를 0으로 초기화
	std::cout << "init pos x: " << init_pos.x << std::endl;
	std::cout << "init pos y: " << init_pos.y << std::endl;

    return 0;
}

실행 결과

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2.

#include <iostream>

int main()
{
    struct MyStruct
    {
		int x;
		int y;
		MyStruct():x(0), y(0) {};
    };

	MyStruct pos;
	std::cout << "pos x: " << pos.x << std::endl;
	std::cout << "pos y: " << pos.y << std::endl;

    return 0;
}

실행 결과

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3. 

#include <iostream>

int main()
{
    struct MyStruct
    {
		int x;
		int y;
		MyStruct()
		{
			memset(this, 0x0, sizeof(struct MyStruct));
		}
    };

	MyStruct pos;
	std::cout << "pos x: " << pos.x << std::endl;
	std::cout << "pos y: " << pos.y << std::endl;

    return 0;
}

실행 결과

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참고

https://stackoverflow.com/questions/1069621/are-members-of-a-c-struct-initialized-to-0-by-default

Are members of a C++ struct initialized to 0 by default?