condition

[SECMoG1T]

How do i express this condition correctly

Condition : i need data.size() to be either divisible by 2 or 3 and greater than 0,
can't understand why my solution here ain't working, yet i think i have done it right.

  while((data.size()%2!=0&&data.size()%3!=0)&&data.size()>0)
    {
      std::cout<<"\n\tAdd data : ";std::cin>>data;
    }

///note : using (data.size()%2!=0||data.size()%3!=0) doesn't work either because
/// true||false== true  meaning that it would require both %2!=0 and %3!=0 to be satisfied 

//for - (data.size()%2!=0&&data.size()%3!=0)
/// it also requires that both conditions be satisfied if am right 

I believe that this one is the only one of it's kind, it's so confusing,what do you think should be done.
thanks.

[jlb]

You seem to have the logic of the modulus incorrect. 3 % 3 should equal zero, meaning the number is divisible by 3.

Also you should consider only calling that function once:

int d;
while(( d = data.size()) > 0 && d %3 == 0 && d % 3 == 0)

[SECMoG1T]

@jib i din't get that very clearly please, what i needed was
data.size() to be either divisible by 2 or 3 and data.size() be greater than 0,

So whenever those conditions are violated the loop should run again: so i believe my modulus logic is in-fact correct.

i would like my function to accept input whose sizes would include

2,3,4,6,8,9,10,12,14,15,16,18,20..

but now my function can only accept input with sizes==

6,12,18

.

[jlb]

What type of variable is data?

Edit:

Does it have a size() member function?

What does size() return?

[SECMoG1T]

Ooh i forgot to mention data is a string variable used to hold character sequences where the size of those sequences in required before evaluation, sorry.

[jlb]

So why are you trying to see if the length of the string is divisible by two or three? Are you sure a string is the correct data type?

What are you inputting into the program?

[coder777]

This:

#include <iostream>
#include <string>
using namespace std;

int main()
{
    string data;
    
  while((data.size()%2!=0&&data.size()%3!=0)||data.size()==0) // Note ||
    {
      std::cout<<"\n\tAdd data : ";std::cin>>data;
    }
    return 0;
}

works for

2,3,4,6,8,9,10,12,14,15,16,18,20..

[SECMoG1T]

Yeah @coder777 that worked thanks, also Thank @jlb for your time pal.

[SECMoG1T]

A question please @coder7777 , it's true that the function works perfectly now but i wouldn't mind a short explanation how this

(data.size()%2!=0&&data.size()%3!=0) is working ,an lost somehow.
thanks.

[coder777]

I'm not sure where your problem is.

The result of data.size()%2!=0 is true when data.size() is not divisible by 2 and that is the required condition for the loop to run. The same applies to data.size()%3!=0.

If you're unsure whether to use && or ||. 'and' excludes while 'or' includes:

1,2,3 and 3,4,5 -> 3
1,2,3 or 3,4,5 -> 1,2,3,4,5

To figure out the behavior you may simulate what a certain expression or a combination thereof does:

#include <iostream>
using namespace std;

int main()
{
  for(int i = 0; i < 10; ++i)
    {
      std::cout << "i->" << i <<": i%2=" << i%2 <<  "  i%3=" << i%3 << endl;
    }
    return 0;
}
//---
i->0: i%2=0 i%3=0
i->1: i%2=1 i%3=1 // Note: Both are not divisible
i->2: i%2=0 i%3=2
i->3: i%2=1 i%3=0
i->4: i%2=0 i%3=1
i->5: i%2=1 i%3=2 // Note: Both are not divisible
i->6: i%2=0 i%3=0
i->7: i%2=1 i%3=1
i->8: i%2=0 i%3=2
i->9: i%2=1 i%3=0
...

[SECMoG1T]

Ooh yeah now I see my ill logic, thank you very much am good now.