diff --git a/day18/ex1-c.c b/day18/ex1-c.c
new file mode 100644
index 0000000..3f6ddfb
--- /dev/null
+++ b/day18/ex1-c.c
@@ -0,0 +1,168 @@
+/* ex1-c: Advent2020 game, day 18/task 1
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define T_SUB    (-1)
+#define T_END    (-2)
+#define T_PLUS   (-4)
+#define T_MULT   (-8)
+#define T_ERR    (-16)
+
+#define DIGIT(c) (((c) >= '0') && ((c) <= '9'))
+
+static long eval_expr();
+
+static char *saveptr=NULL;
+static long get_tok() //, char **saveptr, long *res)
+{
+    char *p, c;
+    long val=0;
+
+    //printf("%s(%p, %p)\n", __func__, ptr, *saveptr);
+    p=saveptr;
+    //printf("%s: str=[%s]\n", __func__, p);
+    while (!val) {
+        c=*p;
+        //printf("  %s: c=[%c] str=[%s]\n", __func__, c, p);
+        switch (c) {
+            case ' ':
+                //case '\n':
+                break;
+            case '(':
+                val=T_SUB;
+                p++;
+                saveptr=p;
+                return eval_expr();
+                break;
+            case ')':
+            case '\n':
+                val=T_END;
+                break;
+            case '*':
+                val=T_MULT;
+                break;
+            case '+':
+                val=T_PLUS;
+                break;
+            default:
+                if (! DIGIT(c)) {
+                    val=T_ERR;
+                    break;
+                }
+                while (DIGIT(c)) {
+                    //printf("   int parse: c=[%c] val=%d\n", c, val);
+                    val=(val*10 + c - '0');
+                    //printf("     -> val=%d\n", val);
+                    p++;
+                    c=*p;
+                }
+                p--;
+                break;
+        }
+        p++;
+    }
+    saveptr=p;
+    //printf("%s END: str=[%s] val=%ld p=[%s]\n", __func__, p, val, *saveptr);
+    return val;
+}
+static char* debug_tok(long tok)
+{
+    static char res[32];
+
+    switch (tok) {
+        case T_END:
+            sprintf (res, "T_END");
+            break;
+        case T_PLUS:
+            sprintf (res, "T_PLUS");
+            break;
+         case T_MULT:
+             sprintf (res, "T_MULT");
+            break;
+         case T_ERR:
+             sprintf (res, "T_ERR");
+            break;
+        case T_SUB:
+            sprintf (res, "T_SUB");
+            break;
+        default:
+            sprintf (res, "TNUM[%ld]", tok);
+            break;
+    }
+    return res;
+}
+
+static long eval_expr()
+{
+    long res=T_SUB, op=T_ERR;
+    long left=0;
+
+    res=get_tok();
+    left=res;
+    printf("--->EVAL TOK=: %ld tag=%s \n", res, debug_tok(res));
+    while (res!=T_ERR && res!=T_END) {
+        switch (res) {
+            case T_END:
+                //printf ("RETURNING: %ld\n", left);
+                //return left;
+                goto end;
+                break;
+            case T_PLUS:
+            case T_MULT:
+                op=res;
+                break;
+            case T_ERR:
+                left=res;
+                //return T_ERR;
+                goto end;
+                break;
+             //case T_SUB:
+             //sprintf (res, "T_SUB");
+             //break;
+            default:
+                //printf ("DEFAULT(left=%ld, res=%ld)\n" , left, res);
+                switch (op) {
+                    case T_PLUS:
+                        left+=res;
+                        break;
+                    case T_MULT:
+                        left*=res;
+                        break;
+                }
+                printf ("DEFAULT(left=%ld, res=%ld) - " , left, res);
+                printf ("New left: %ld\n", left);
+                break;
+        }
+        res=get_tok();
+        printf("get_tok: %ld tag=%s \n", res, debug_tok(res));
+        // printf("get_tok: %ld tag=%s \n", res, debug_tok(res));
+
+    }
+end:
+    printf ("RETURNING: %ld\n", left);
+    return left;
+}
+
+int main(ac, av)
+    int ac;
+    char **av;
+{
+    char line[1024];
+    long res=0, tmp;
+
+    while (fgets(line, sizeof line, stdin)) {
+        //*(line+strlen(line)-1)=0;
+        saveptr=line;
+        //printf("get_tok: %ld tag=%s \n", res, debug_tok(res));
+        tmp=eval_expr();
+        printf("EXPR=%s\n", debug_tok(tmp));
+        res+=tmp;
+        //} while (res!=T_ERR && res!=T_END);
+            //res+=build_tree(line, &pnext);
+    }
+    printf("%s : res=%ld\n", *av, res);
+    exit (0);
+}