Committing days 1-4

01/01test.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+// Returns -1 if a string is not a number (e.g. 'two')
+// Otherwise, returns the number.
+// Only works for single digits.
+// Only accepts lower case.
+int8_t parse_num(char *str)
+{
+    const char *num_strings[10] =  { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
+
+    // The lengths of the strings above, 
+    const uint8_t num_string_lens[10] =  { 4, 3, 3, 5, 4, 4, 3, 5, 5, 4 };
+
+    bool possible_nums[10] = { [0 ... 9] = true };
+    uint8_t num_idx = 0;
+    uint8_t char_incriment = 0;
+    char current;
+    bool result_still_possible = false;
+
+    for (char_incriment = 0; char_incriment < 6; char_incriment++)
+    {
+        // Grab out next character in the string
+        current = *(str + char_incriment);
+
+        for (num_idx = 0; num_idx < 10; num_idx++)
+        {
+            if (!possible_nums[num_idx]) continue;
+
+            // If we have passed the end of our number string and every character has matched,
+            // then we return our valid character.
+            if (char_incriment == num_string_lens[num_idx] && possible_nums[num_idx]) return num_idx;
+
+            // If the character is not the letter it should be, disqualify this number.
+            // e.g. if num_idx == 1 and char_incriment == 2, current should equal 'e'
+            // because 'e' is the 3rd number in the word 'one.'
+            if (current != num_strings[num_idx][char_incriment]) possible_nums[num_idx] = false;
+            else result_still_possible = true;
+        }
+        if (!result_still_possible) return -1;
+    }
+
+    return -1;
+}
+
+int main(int argc, char **argv) {
+
+    const char *num_strings[10] =  { "zerorr", "oneqw", "twoqw", "threere", "fourer", "fiveer", "sixer", "sevener", "eighter", "nineer" };
+
+    uint8_t i = 0;
+
+    for (i = 0; i < 10; i++)
+    {
+        printf("%d\n", parse_num(num_strings[i]));
+    }
+
+    return 0;
+}