STC89C52單片機四則運算出錯

ID:160658 · 發表于 2018-11-5 18:13

設：bufTime.year = 18, bufTime.mon = 11, bufTime.day = 4算出的w的值等于2，正確值應該是0。不知是什么原因，望大俠們指點，先謝謝了！

void RefreshTimeShow()
{
unsigned int d, m, y, w;

ShowBcdByte(16, 0, bufTime.year);       //Year
ShowBcdByte(48, 0, bufTime.mon);       //Month
ShowBcdByte(80, 0, bufTime.day);       //Date
ShowBcdByte(0, 2, bufTime.hour);       //Hour
ShowBcdByte(32, 2, bufTime.min);       //Minutes
ShowBcdByte(64, 2, bufTime.sec);       //Seconds

d = bufTime.day;
m = bufTime.mon;
y = 2000 + bufTime.year;

if(m == 1 || m == 2)
{
      m += 12;
      y--;
}
w = (d + 1 + 2*m + 3*(m+1)/5 + y + y/4 - y/100 + y/400)%7;
bufTime.week = (unsigned char)w;
ShowBcdByte(32, 4, bufTime.week);
}