C语言 输入年月日判断是第几天

判断输入年份为闰年还是平年.主要用于判断二月份的天数.

int isLeapYear(int year);
int isLeapYear(int year) {
    int february = 0;
    if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {
        february = 29;
    } else {
        february = 28;
    }
    return february;
}int isLeapYear