function that chooses action based on integer value

[Lvl80RetPaladin]

What's that one function that, based on the integer value of the input, will choose an action? The one that uses cases and such.

[histrungalot]

Maybe assert??

[zerobandwidth]

I believe you're looking for switch().

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

string talkBack( int x )
{
  stringstream buf ( stringstream::out ) ;  // excessive but bear with me

  switch(x)
  {
    case 1:  // That is, x == 1
      buf << "Hello.  " ;
      // No "break" statement here, so case 1 will also "leak" into case 2.
    case 2:  // x == 2
      buf << "How are you?" ;
      break ;
    case 3:  // x == 3
    { // Because the code for case 3 declares variables, you have to
      // put it in braces, sort of like an inline function definition.
      // Some people might even prefer to style all case blocks this way.
      buf << "I can count to three!"
      int i = 0 ;
      do { buf << "  " << ++i ; } while( i < 3 ) ;
    } break ;
    default: // Magic label for code to be executed when no case value matches.
      buf << "Huh?" ;
  }

  return buf.str() ;
}

int main()
{
  for( int i = 0 ; i < 4 ; i++ )
    cout << talkBack(i) << endl ;
  return 0 ;
}

Of course this is all off the top of my head and I haven't bothered testing it but if you try it I expect that you'd get this output:

Huh?
Hello.  How are you?
How are you?
I can count to three!  1  2  3

In general, the following two code blocks are exactly equivalent:

switch(x)
{
  case a:  /* stuff A */ ; break ;
  case b:  /* stuff B */ ; break ;
  case c:  /* stuff C */ ; break ;
  default: /* stuff D */ ;
}

...and...

if( x == a )      { /* stuff A */ ; }
else if( x == b ) { /* stuff B */ ; }
else if( x == c ) { /* stuff C */ ; }
else { /* stuff D */ ; }

The useful difference is that switch() will let you "leak" from one block of stuff into another by leaving out the break ; statement at the end of a case block, as I illustrated above.

FYI, the switch() syntax is also used in Java.

I hope this helps.