alpha-numeric to numeric program

The following program is converting alpha-numeric phone number to numeric. The problem i am having is that it is giving me a link error and i am not sure why. Can anyone help out Thanks.

Code:

   #include <stdio.h>#include <ctype.h>




#define SIZE 30


void convNum( char *phoNum)
{   
    int x=0; 
    phoNum[SIZE];  
    
    printf("Enter the phone number:"); 




    while (gets(phoNum)!=NULL)
    {
       
     switch(toupper(phoNum[x]))
     {
     case 'A': 
     case 'B': 
     case 'C': 
          phoNum[x]=2; 
          break; 
     case 'D': 
     case 'E': 
     case 'F': 
          phoNum[x]=3; 
          break; 
     case 'G': 
     case 'H': 
     case 'I': 
          phoNum[x]=4; 
          break; 
     case 'J': 
     case 'K': 
     case 'L': 
          phoNum[x]=5; 
          break; 
     case 'M':
     case 'N': 
     case 'O': 
          phoNum[x]=6; 
          break; 
     case 'P': 
     case 'Q': 
     case 'R': 
     case 'S': 
          phoNum[x]=7; 
          break; 
     case 'T': 
     case 'U': 
     case 'V': 
          phoNum[x]=8; 
          break; 
     case 'W': 
     case 'X': 
     case 'Z': 
          phoNum[x]=9; 
          break; 
          }
     for (x; x<SIZE; x++)
    {
        printf("%c", phoNum[x]); 
    } 
    
   }
 }

The entry point of a C program is a function named main(), which you are required to provide. main() calls other functions as needed in order to implement required functionality. The code you have shown does not provide a main() function. That will cause a linker error.

> The problem i am having is that it is giving me a link error and i am not sure why.
Neither do we, since you didn't actually post the actual error messages.

If you're compiling / linking with the GCC toolchain, it could be warning you (again) that gets() is deprecated.
But when you do resolve your linker issue, please do the world a favour by typing in say a 60 character phone number, just for the hell of it.

> Can anyone help out
At this moment, it seems doubtful