Optional comma in C initialization

#include <stdio.h>

struct person {
	int sex; 
	int no;
};

int main(int argc, const char *argv[]) {
	int array_1[3] = {1, 2, 3};
	int array_2[3] = {1, 2, 3,};
	struct person xiao_yu = {
		1, 100
	};
	struct person xiao_yue = {
		1, 100,
	};

	return 0;
}

 

Refer to 6.7.8 in C99 standard.