指定初始化器代码错误

不知道哪里出错了，怎么改都不对，求解！

#include<stdio.h>
#define MONTHS 12
int main()
{
    int days [MONTHS] = { 31, 28,[4] = 31, 30, 31,[1] = 29 };
    int i;
    for (i = 0; i < MONTHS; i++)
        printf("%2d %d\n", i + 1, days[i]);
    return 0;
}

int days[MONTHS] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

int days [MONTHS] = { 31, 28,[4] = 31, 30, 31,[1] = 29 };初始化错误