easy if / else question...

Hi

I've got comparable code:

Code:

---

if (strstr(string, "Statement1")
        function1;
if (strstr(string, "Statement2")
        function2;
if (strstr(string, "Statement3")
        function3;
if (strstr(string, "Statement4")
        function4;

---

Problem: I need a default case... I could solve it with a flag like this:

Code:

---

if (strstr(string, "Statement1")
{
        function1;
        flag=TRUE;
}
if (strstr(string, "Statement2")
{
        function2;
        flag=TRUE;
}

....

if(!flag)
{
        fuction_default;
}

---

or maybe like this

Code:

---


if (strstr(string, "Statement1")
{
        function1;
}
else
{
        if (strstr(string, "Statement2")
        {
                function2;
        }
        else
        {
                if (strstr(string, "Statement3")
                {
                        function3;
                }
                else
                {
                        if (strstr(string, "Statement4")
                        {
                                function4;
                        }
                        else
                        {
                                fuction_default;                       
                        }
                }
        }
}

---

??

I dont think its the best way... I suppose that a "switch - case statement" is unfortunately not possible because I need to search the string for many different char-strings...
How would you solve this problem?

thx in advance

I'd put the search in a void return function

Code:

---

void evaluate( const string & str )
{
  if (strstr(string, "Statement1")
  {
    function1;
    return;
  }
  if (strstr(string, "Statement2")
  {
    function2;
    return;
  }
  ...
  ...

  fuction_default();
}

---

It might be more OO to use a class though.
Derive all the functions from an abstract base function interface.
Have a container class that holds base function pointers with associated strings eg. statement1 with function1.
The container class can then have methods like add_function(statement1,function1) and add_default(function_default).
Finally a call to the conatiner class with a string will evaluate the correct function.
The controller can be responsible for destroying the functions.
"strstr" can be implemented within the controller.
The benefit of this is that new function/string pairs can be added easily and dynamically.
Also the complexity is wrapped up for client code eg.

Code:

---

  // At start-up
  Controller C;
  C.add_function("Statement1",new Function1());
  C.add_function("Statement2",new Function2());
  C.add_function("Statement3",new Function3());
  ...
  ...
  C.add_default(new DefaultFunction1());

  // When the call is needed
  C.evaluate( RuntimeString );

---

Cheers,
ljhw

I would do:

Code:

---

if (strstr(str, "item1"))
    ; // do something
else if (strstr(str, "item2"))
    ; // do something
else if (strstr(str, "item3"))
    ; // do something
else if (strstr(str, "item3"))
    ; // do something
else if (strstr(str, "item4"))
    ; // do something
else if (strstr(str, "item5"))
    ; // do something
else {
    // catch all other casees here
}

---

Thank you both for your answers... I did it exactly like j0nas said and it works fine!! :D

:thumb:
Greetz