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day18 C part 1, 1st tentative (with tons of printf)

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Bruno Raoult
2021-07-19 17:23:56 +02:00
parent 7a2a23782d
commit 493c5089b3
1 changed files with 168 additions and 0 deletions
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day18/ex1-c.c Normal file
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/* 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);
}