Translating alphabetic number in C

[crystal2005]

Hi guys,

Just like the title, i'm looking for the example of C program that translates an alphabetic phone number into numeric. The idea as the following output

Enter phone number: 1800-TEST-100

result: 1800-8378-100

so basically 2=ABC, 3=DEF, 4=GHI, . . . , 9 = WXYZ

So, all the non-alphabetic (E.g. dash, punctuations) will leave unchanged.

Can anyone give the pseudo code of how to handle the string input of the above idea??

Thank you.

[ricardopf]

Actually, it seems to be an "light problem"...
All you need to do is write an "while" or a "for" loop.
The loop should go from 0 (zero) to the ALPH_PHONE_SIZE-1.
Probably you will read the phone from the user and store the information in a array char (or string).
Then, inside the loop you should access each position of this array/string and compute the information.
If you use a "while" loop you must keep a counter manually in order to access the array/string positions gradually. Otherwise, using a "for" loop you access the position with the loop control variable.
To know what character is the contend of a specific array/string position, you can implement a "switch:cas e" structure.
For example:

...
// inside the loop
switch (phone_array[POS]):
   case 'a':
   case 'b':
   case 'c':
      value = 2;
      break;
   case 'd':
   case 'e:
   case 'f':
      value = 3;
      break;
...
   default:
      break;
...
 

[newb16]

If maintainability is not an issue, I'd rather use lookup array and index it by input letter ( converted to upper case beforehand):
res = lookup[letter-'A'];
where array is like
int lookup[] = {2,2,2,3,3, ... };

[whodgson]

The following comments explain the code amplified algorithm. The convert() function is certainly a bit clunky and could do with an oil change.

{char a[25]={0};                            
char c=0;
while(cin.get(c) )                        //get the alpha-numeric string
{ for(int i=0;i<25;i++)
 a[i]=c;                                      //place each in array
 if(c>=0 && c<=9)cout.put(c);       //traverse array and print integers
 else if(c>='A' && c<='Z')convert(c);  //call func to convert text
 else cout.put(c);}                        //print any integers which follow
}

End input with Ctrl+Z.

char convert (char c)         //convert function - text to ints
{
switch (c)
{case 65:cout<<"2";break; //A
 case 66: cout<<"2";break; //B
 case 67: cout<<"2";break; //C    
 case 68: cout<<"3";break; //D
 case 69: cout<<"3";break; //E       
 case 70: cout<<"3";break; //F
............etc.......................... 
case 87: cout<<"9";break; //W
 case 88: cout<<"9";break; //X    
 case 89: cout<<"9";break; //Y
 case 90: cout<<"9";break; //Z       
 default:cout<<" ";break; }                     
}

/*
This is typical output.
1300-WIDER-32541-100^Z
1300-94337-32541-100

1800-THINNER-25416-100^Z
1800-8446637-25416-100^Z
Press any key to continue . .
*/
End program with another Ctrl+Z
Hope this helps.

[JosAH]

@whodgson
Please don't try to outsmart anything and don't use those absolute values; your code fails horribly on non-ASCII encoding machines (EBCDIC is still around and alive and kicking). Use symbolic constants instead: 'A', 'B', 'C' etc. Your compiler knows what to do with them.

kind regards,

Jos

[whodgson]

The convert() function in thread #4 was badly written and wrong.
It should have been expressed as follows:
char convert (char c)
{
switch (c)
{case 'A':cout<<"2";b reak;
case 'B': cout<<"2";break ;
case 'C': cout<<"2";break ;
case 'D': cout<<"3";break ;
case 'E': cout<<"3";break ;
case 'F': cout<<"3";break ;
--------------etc-------------------
case 'S': cout<<"7";break ;
case 'T': cout<<"8";break ;
case 'U': cout<<"8";break ;
case 'V': cout<<"8";break ;
case 'W': cout<<"9";break ;
case 'X': cout<<"9";break ;
case 'Y': cout<<"9";break ;
case 'Z': cout<<"9";break ;
default:cout<<" ";break; }
}
Thanks JosAH.....afrai d am a VSL

[JosAH]

Why not use the short solution given in reply #3? Something like this:

char* d= "222333444 ... 77778889999";
if (c >= 'A' && c <= 'Z') cout << d[c-'A'];
 

kind regards,

Jos

[crystal2005]

@whodgson

Ahh... this works fine. Thanks a lot guys :)

But my program has different implementation. I used for loop to traverse all the character inside the char array and put the array into the switch case.

[whodgson]

I couldn`t see how Newb16`s lookup worked and thought that it was a germ of an idea that had to be developed. Now that you`ve repeated it, think I can see
(vaguely) its meaning....... so will have a play with it. Thanks to you both.