The decimal structure

Use the decimal data type to declare host variables for database values of type DECIMAL.

A structure of type decimal represents a value in a decimal host variable, as follows:

#define DECSIZE 16

struct decimal
   {
   short dec_exp;
   short dec_pos;
   short dec_ndgts;
   char  dec_dgts[DECSIZE];
   };

typedef struct decimal dec_t;

The decimal.h header file contains the decimal structure and the typedef dec_t. Include this file in all C source files that use any decimal host variables with the following include directive:

EXEC SQL include decimal;

The decimal structure stores the number in pairs of digits. Each pair is a number in the range 00 - 99. (Therefore, you can think of a pair as a base-100 digit.) The following table shows the four parts of the decimal structure.

Table 1. Fields in the decimal structure
Field	Description
dec_exp	The exponent of the normalized decimal type number. The normalized form of this number has the decimal point at the left of the left-most digit. This exponent represents the number of digit pairs to count from the left to position the decimal point (or as a power of 100 for the number of base-100 numbers).
dec_pos	The sign of the decimal type number. The dec_pos field can assume any one of the following three values: `1`: when the number is zero or greater `0`: when the number is less than zero `–1`: when the value is null
dec_ndgts	The number of digit pairs (number of base-100 significant digits) in the decimal type number. This value is also the number of entries in the dec_dgts array.
dec_dgts[]	A character array that holds the significant digits of the normalized decimal type number, assuming dec_dgts[0] ! = 0. Each byte in the array contains the next significant base-100 digit in the decimal type number, proceeding from dec_dgts[0] to dec_dgts[dec_ndgts].

The following table shows some sample decimal values.

Table 2. Sample structure field values for decimal
Value	dec_exp	dec_pos	dec_ndgts	dec_dgts[]
-12345.6789	3	0	5	dec_dgts[0] = 01 dec_dgts[1] = 23 dec_dgts[2] = 45 dec_dgts[3] = 67 dec_dgts[4] = 89
1234.567	2	1	4	dec_dgts[0] = 12 dec_dgts[1] = 34 dec_dgts[2] = 56 dec_dgts[3] = 70
-123.456	2	0	4	dec_dgts[0] = 01 dec_dgts[1] = 23 dec_dgts[2] = 45 dec_dgts[3] = 60
480	2	1	2	dec_dgts[0] = 04 dec_dgts[1] = 80
.152	0	1	2	dec_dgts[0] = 15 dec_dgts[1] = 20
-6	1	0	1	dec_dgts[0] = 06

You can use the deccvasc demonstration program to experiment with how stores decimal numbers.