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#include "loans.h"
contract *mort_init(int n, int d, double r, double P) {
if ((n < 0)) return NULL;
if ((d >= n)||(d < 0)) return NULL;
contract *c = (contract *)calloc(1, sizeof(contract));
c->n = (unsigned int)n;
c->d = (unsigned int)d;
c->r = r;
c->P = P;
return c;
}
double mort_update(contract *c) {
double tmp;
if (c->k > c->n)
return 0.0;
if (c->k == c->d) {
if (c->r == 0.0) {
c->A = c->P / c->n;
} else {
tmp = pow(1.0 + c->r, (double)(c->n - c->k));
c->A = - (c->P * c->r * tmp);
c->A = c->A / (1.0 - tmp);
}
}
c->k++;
c->I = c->r * c->P;
if (c->k <= c->d)
c->P += c->I;
else {
c->D = c->A - c->I;
c->P = c->P - c->D;
/* c->A is fixed ! */
}
return c->A;
}
void mort_free(contract *c) {
free(c);
}
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