Hi: I use c8051f410,
Program Size: data=114.1 xdata=100 code=4633
I had to use the long multiple in program and find it can not be excecute properly.
The code is as below, Is this stack overflow? How can I fix it?
long x=0; char cHour=0xff; char cMin=0xff; char cSec=0xff; long gulbegintime=0; x=(ulong)3600*(ulong)cHour; printf("1 x =%lu \n",x); gulbegintime=60*cMin; printf("2 gulbegintime =%lu \n",gulbegintime); gulbegintime+=cSec; printf("3 gulbegintime =%lu \n",gulbegintime);
print result:
1 x =4294963696 2 gulbegintime =4294967236 3 gulbegintime =4294967235
it can not be excecute properly
Actually, it does execute properly. The results are correct according to the language standard. Prior to the multiplication, (char)0xFF is converted to 0xFFFFFFFFUL. If want it to be 0xFFUL, use unsigned char instead of char.
YOU SAID ### (char)0xFF is converted to 0xFFFFFFFFUL ###
ONLY WHEN CHAR IS SIGNED. THE SIGNEDNESS IT IS IMPLEMENENTATION SPECIFIC. SEE PAGE 47 OF THE MANUAL.
Good point. That's why it's important to explicitly state the signedness of char where it matters. Better yet, use type names like uint8_t for numbers. char should only be used for actual characters.
YOU SAID ### Good point ###
THANK YOU FOR THE SUPPORT. I LEARN PROGRAMING FROM THE BOOK. IT IS VERY GOOD. ONE DAY I WANT TO WRITE A REAL PROGRAM.
Can't you do your trolling in lower case letters?
YOU SAID ### Can't you do your trolling in lower case letters? ###
I GAVE A GOOD POINT. WHAT HAVE YOU DONE TODAY? NOTHING.
OF COURSE I MEANT I RAISED A GOOD POINT.
WHAT HAVE YOU DONE TODAY
.... is stopped asnnoying evryone with your SHOUTING Erik