Add day 1 in C

2019/1/day1.c

@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int cost(int mass) {
+    return mass / 3 - 2;
+}
+
+int costRec(int mass, int acc) {
+    int c = cost(mass);
+    if (c <= 0) {
+        return acc;
+    }
+    return costRec(c, acc+c);
+}
+
+int part1() {
+    FILE* inputFile = fopen("input", "r");
+    char line [10];
+
+    int fuel = 0;
+    while (fgets(line, sizeof(line), inputFile)) {
+        fuel += cost(atoi(line));
+    }
+    fclose(inputFile);
+    
+    return fuel;
+}
+
+int part2() {
+    FILE* inputFile = fopen("input", "r");
+    char line [10];
+
+    int fuel = 0;
+    while (fgets(line, sizeof(line), inputFile)) {
+        fuel += costRec(atoi(line), 0);
+    }
+    fclose(inputFile);
+    
+    return fuel;
+}
+
+int main(int argc, char *argv[]) {
+
+    printf("Part 1: %d\n", part1());
+    printf("Part 2: %d\n", part2());
+    return 0;
+}