coding_practice/AoC/2023/trebuchet/trebuchet.c

#include <stdio.h>
#include <stdlib.h>
// Just part 1
int main(int argc, char **argv) {

  char c;
  int sum = 0;
  int first = -1, last = -1;
  while ((c = getchar()) != EOF) {

    if (c == '\n') {
      sum += last != -1 ? first*10 + last : first*10 + first;
      first = -1;
      last = -1;
    } else {
      if (c <= '9' && c >= '0') {
        if (first == -1) {
          first = c - '0';
        } else {
          last = c - '0';
        }
      }
    }
  }
  printf("%d\n", sum);

  return 0;
}