the system tell me "the days is not defined":will there anyone help me?

[wild wolf]

#include <iostream>

int main()
{
 int year,month,date,days,feb;
 cout<<"please input a date（eg. 2010 8 10)";
 cin>>year>>month>>date;
 if((year%4==0&&year%100!=0)||year%400==0) 
  feb=29;
 else 
  feb=28;
 switch (month)
 {
  case 12: days=30;
  case 11: days=days+31;
  case 10: days=days+30;
  case 9: days=days+31;
  case 8: days=days+31;
  case 7: days=days+30;
  case 6: days=days+31;
  case 5: days=days+30;
  case 4: days=days+31;
  case 3: days=days+feb;
  case 2: days=days+31;
  case 1: days=days+0;
 }
 days=days+date;
 cout<<"The day is the"<<days<<"in a year";
 return 0;
}

[Oralloy]

Try initializing days; it looks like you're getting a warning about days not having an assigned value at "case 12"

int year,month,date,days=0,feb;

Good Luck!

[wild wolf]

I have tryed to give the days a first value. but it seemed that it is not this matter....

[weaknessforcats]

This compiles OK with Visual Studio.NET 2008.

What error, exactly, are you getting?

[Oralloy]

Post the exact error message, please?

Also, your switch doesn't have a default branch - unless you initialize days, the compiler can't count on days being assigned at the point where you add date to it.

[wild wolf]

this is the error image. And i download a vc++ 6.0 for it , find it is ok despite of the wrong result …… In addition ， i add the "using namespace std;"

[Oralloy]

The error message is telling you that there is a code path where days is used without first being initialized to a known value.

So why doesn't the initialization of days as part of its definition resolve the warning that you're getting?

I suppose the other thing you could do is move days to a definition of its own, like this:

int days = 0;

Try it, and good luck. I just don't see what's wrong, otherwise.

[wild wolf]

it is successful , i use vc++ to compile it . you are right , when i give 0 to the days , it return a right result , thank you for your help^^

[Oralloy]

@wild_wolf,

You are quite welcome.

I learned something about the compiler's eccentricities, as well.

Cheers!