added mortgage loans

1 files changed, 31 insertions, 0 deletions

diff --git a/mortgage_loan.c b/mortgage_loan.c
new file mode 100644
index 0000000..386828a
--- /dev/null
+++ b/mortgage_loan.c
@@ -0,0 +1,31 @@
+#include "loans.h"
+
+contract *mort_init(int n, int d, float r, float 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;
+	c->A = - (P * r * powf(1.0f + r, (float)n));
+	c->A = c->A / (1.0f - powf(1.0f + r, (float)n));
+
+	return c;
+}
+
+float mort_update(contract *c) {
+	if (c->k > c->n)
+		return 0.0f;
+	c->k++;
+	c->I = c->r * c->P;
+	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);
+}