Add problem 9 solution

include/p9.h

@@ -0,0 +1,14 @@
+#ifndef P9_H
+#define P9_H
+
+typedef struct {
+	int id;
+	char name[32];
+	double price;
+	int stock;
+} Product;
+
+Product* find_product(Product* products, int num_products, int id);
+
+#endif
+

src/main.c

@@ -8,6 +8,7 @@
 #include "p6.h"
 #include "p7.h"
 #include "p8.h"
+#include "p9.h"
 
 void print_int_arr(int* arr, int size) {
 	for (int i = 0; i < size; ++i) {
@@ -95,6 +96,24 @@ int main(void) {
 
 	printf("Average GPA: %.2lf\n", average_gpa);
 
+	// Problem 9
+	printf("Problem 9:\n");
+
+	Product products[4] = {
+		{ 4011, "Banana", 10.0, 1000 },
+		{ 412, "Apple", 2.5, 240 },
+		{ 728, "Pear",  4.8, 180 },
+		{ 119, "Orange", 1.6, 438 },
+	};
+
+	Product* found = find_product(products, 4, 728);
+
+	if (found != NULL) {
+		printf("Found product \"%s\" with id %d\n", found->name, found->id);
+	} else {
+		printf("Did not find any matching products!\n");
+	}
+
 	return 0;
 }
 

src/p9.c

@@ -0,0 +1,16 @@
+#include "p9.h"
+
+#include <stddef.h>
+
+Product* find_product(Product* products, int num_products, int id) {
+	Product* found = NULL;
+
+	for (int i = 0; i < num_products; ++i) {
+		if (products[i].id == id) {
+			found = &products[i];
+		}
+	}
+
+	return found;
+}
+