day 2

Signed-off-by: Jack Bond-Preston <jackbondpreston@outlook.com>

2/2.c

@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define PARTB
+
+int main() {
+    FILE *f = fopen("input.txt", "r");
+    if (!f) return 1;
+
+    char opcode[16];
+    int operand = 0, ret = 0;
+
+    int depth = 0, distance = 0, aim = 0;
+
+    int processed = 0;
+
+    while ((ret = fscanf(f, "%s %d", opcode, &operand)) > 0) {
+        switch (opcode[0]) {
+            case 'f': //forward
+                distance += operand;
+#ifdef PARTB
+                depth    += aim * operand;
+#endif
+                break;
+            case 'd': //down
+#ifndef PARTB
+                depth += operand;
+#else
+                aim   += operand;
+#endif
+                break;
+            case 'u': // up
+#ifndef PARTB
+                depth -= operand;
+#else
+                aim   -= operand;
+#endif
+                break;
+        }
+
+        printf("%d\n", aim);
+
+        processed++;
+    }
+
+    printf("finished processing %d instrs\n", processed);
+    printf("final depth: %d, distance: %d\n", depth, distance);
+    printf("mult: %d*%d=%d\n", distance, depth, distance * depth);
+
+    return 0;
+}