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/* ------------------------------------------------------------------ */
/* Decimal Number Library Demonstration program */
/* ------------------------------------------------------------------ */
/* Copyright (c) IBM Corporation, 2001. All rights reserved. */
/* ----------------------------------------------------------------+- */
/* right margin -->| */
// example2.c -- calculate compound interest
// Arguments are investment, rate (%), and years
#define DECNUMDIGITS 38 // work with up to 38 digits
#include "decNumber.h" // base number library
#include <stdio.h> // for printf
int main(int argc, char *argv[]) {
int need=3;
if (argc<need+1) { // not enough words
printf("Please supply %d number(s).\n", need);
return 1;
}
{ // excerpt for User's Guide starts here--------------------------|
decNumber one, mtwo, hundred; // constants
decNumber start, rate, years; // parameters
decNumber total; // result
decContext set; // working context
char string[DECNUMDIGITS+14]; // conversion buffer
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);
decNumberFromString(&start, argv[1], &set); // parameter words
decNumberFromString(&rate, argv[2], &set);
decNumberFromString(&years, argv[3], &set);
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
decNumberToString(&total, string);
printf("%s at %s%% for %s years => %s\n",
argv[1], argv[2], argv[3], string);
} //---------------------------------------------------------------|
return 0;
} // main
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