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/* ------------------------------------------------------------------ */
/* Decimal Number Library Demonstration program */
/* ------------------------------------------------------------------ */
/* Copyright (c) IBM Corporation, 2001. All rights reserved. */
/* ----------------------------------------------------------------+- */
/* right margin -->| */
// example6.c -- calculate compound interest, using Packed Decimal
// Values are investment, rate (%), and years
#include "decPacked.h" // base number library
#include <stdio.h> // for printf
int main(int argc, char *argv[]) {
{ // excerpt for User's Guide starts here--------------------------|
decNumber one, mtwo, hundred; // constants
decNumber start, rate, years; // parameters
decNumber total; // result
decContext set; // working context
uint8_t startpack[]={0x01, 0x00, 0x00, 0x0C}; // investment=100000
int32_t startscale=0;
uint8_t ratepack[]={0x06, 0x5C}; // rate=6.5%
int32_t ratescale=1;
uint8_t yearspack[]={0x02, 0x0C}; // years=20
int32_t yearsscale=0;
uint8_t respack[16]; // result, packed
int32_t resscale; // ..
char hexes[49]; // for packed->hex
int i; // counter
if (argc<0) printf("%s", argv[1]); // noop for warning
decContextDefault(&set, DEC_INIT_BASE); // initialize
set.traps=0; // no traps
set.digits=25; // precision 25
decNumberFromString(&one, "1", &set); // set constants
decNumberFromString(&mtwo, "-2", &set);
decNumberFromString(&hundred, "100", &set);
decPackedToNumber(startpack, sizeof(startpack), &startscale, &start);
decPackedToNumber(ratepack, sizeof(ratepack), &ratescale, &rate);
decPackedToNumber(yearspack, sizeof(yearspack), &yearsscale, &years);
decNumberDivide(&rate, &rate, &hundred, &set); // rate=rate/100
decNumberAdd(&rate, &rate, &one, &set); // rate=rate+1
decNumberPower(&rate, &rate, &years, &set); // rate=rate^years
decNumberMultiply(&total, &rate, &start, &set); // total=rate*start
decNumberRescale(&total, &total, &mtwo, &set); // two digits please
decPackedFromNumber(respack, sizeof(respack), &resscale, &total);
// lay out the total as sixteen hexadecimal pairs
for (i=0; i<16; i++) {
sprintf(&hexes[i*3], "%02x ", respack[i]);
}
printf("Result: %s (scale=%ld)\n", hexes, (long int)resscale);
} //---------------------------------------------------------------|
return 0;
} // main
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