Converting a character array of packed decimal to integer in C program

Question

I need to write a C program to convert packed decimal field in a buffer to in integer value. The precision of packed decimal is 9 and Scale is 0. What is the best way to convert this in a IBM mainframe C progrram? In Cobol the format for Packed Decimal used is Comp-3 Any help is aprreciated.

There are are many questions related to Comp-3. But in Comp-3 123 is represented '123c' and -123 as '123d'. There are 2 approaches - convert to string and then to a number (see http://stackoverflow.com/questions/4337912/how-to-convert-unpacked-decimal-back-to-comp-3) or access the nybles (see http://stackoverflow.com/questions/142972/c-convert-comp-3-packed-decimal-to-human-readable-value) — Bruce Martin, Apr 10 '14 at 22:16

score 1 · Answer 1 · answered Apr 11 '14 at 06:01

1

If you are running the program on a Zos mainframe then the C compiler supports packed decimal natively.

Google for "Zos C fixed point decimal type" should get you the right manual page its a simple as :

#include <decimal.h>
decimal(9,0) mynum;

answered Apr 11 '14 at 06:01

James Anderson

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1

Thanks for your response. But I think it will not resolve the question.I have a buffer as char * that needs to be converted to decimal(9,0), And I am not sure if can not do: decimal(9,0) mynum = charBuffer; or decimal(9,0) mynum = (decimal(9,0))charBuffer; – Amit Sood Apr 11 '14 at 21:10

score 1 · Answer 2 · answered Apr 11 '14 at 21:06

The one way I think it can be done, is
long long MyGetPackedDecimalValue(char* pdIn, int length)
{   
    // Convert packed decimal to long   
   const  int PlusSign = 0x0C;       // Plus sign   
   const int MinusSign = 0x0D;      // Minus   `enter code here`
   const int NoSign = 0x0F;         // Unsigned   
   const int DropHO = 0xFF;         // AND mask to drop HO sign bits   
   const int GetLO  = 0x0F;         // Get only LO digit   
    long long val = 0;                    // Value to return    

    printf ("in side ****GetPDVal \n ");
   for(int i=0; i < length; i++)
    {   
      int aByte = pdIn[i] & DropHO; // Get next 2 digits & drop sign bits   
      if(i == length - 1)
        {    // last digit?   
         int digit = aByte >> 4;    // First get digit   
         val = val*10 + digit;   
            printf("digit= %d, val= %lld \n",
                digit,
                val);   
         int sign = aByte & GetLO;  // now get sign   
         if (sign == MinusSign)
            {
            val = -val;
            }
         else 
            {   
            // Do we care if there is an invalid sign?   
            if(sign != PlusSign && sign != NoSign)   
               perror("SSN:Invalid Sign nibble in Packed Decimal\n");   
         }   
      }
        else
        {   
         int digit = aByte >> 4;    // HO first      
         val = val*10 + digit;   
            printf("digit= %d, val= %lld \n",
                digit,
                val);   
            digit = aByte & GetLO;      // now LO   
         val = val*10 + digit;   
            printf("digit= %d, val= %lld \n",
                digit,
                val);   
      }   
   }`enter code here`
    printf ("**** coming out GetPDVal \n ");
    return val;
}

Converting a character array of packed decimal to integer in C program

2 Answers2