C without the braces

Question

My challenge is language-specific, but needs a lot of creativity: write a valid C program with only one pair of braces {} and none of the keywords if, for, while (all checked after preprocessing, and after substituting trigraphs). I'm looking for preprocessor abuse (but other methods are also welcome) to define a new pseudo-language which supports at least if/else, then use that language to do something cool.

That's pretty easy, and I'll just score this by upvotes since any scoring would be rather arbitrary, but here are some things which would be impressive:

• function calls (also arguments, return values);
• else if;
• switch/case (also default, fall-through);
• for or while (super-impressive. Also break, continue);
• having only one semicolon ; (This one makes the challenge a bit different);
• an interesting program;
• full portability (portable in practice is good, portable in theory is even better).

This isn't about obfuscation. The preprocessor statements will probably be a bit hairy, but the actual code should be very easy to follow.

goto is allowed, but I believe it won't help much.

Answer 1

Doesn't seem too hard....

#include <stdio.h>

int main(void) {
  printf("I only used one pair of braces!\n");
  printf("This is easy...\n");
  printf("Lalalalala\n");
  getchar();
  return 0;
}

having only one semicolon ; (This one makes the challenge a bit different);

Oh, also easy:

int main(void) {
  return 0;
}

else if;

How about goto and ternary operator abuse?

#include <stdio.h>

int main(void) {
  int testNum = 5;
  void *whichSection = testNum < 0 ? &&ifSection :
                       (testNum == 0 ? &&elseIfSection : &&elseSection);
  goto *whichSection;
  ifSection:
    printf("Number is negative\n");
    goto end;
  elseIfSection:
    printf("Number is zero\n");
    goto end;
  elseSection:
    printf("Number is positive and nonzero\n");
    goto end;
  end:
    return 0;
}

switch/case (kinda) (also default (kinda), fall-through (yes))

for (no) or while (no) (super-impressive. Also break (yes), continue (no));

My above solution is a bit like that - the goto is break, the elseSection is default, fall-through works, etc.

full portability (portable in practice is good, portable in theory is even better).

All of my solutions have this.

---

we code golfers are infamous for bending the rules :D

Answer 2

We can simulate a conditional branch in this manner:

int condition = /* insert some condition here, like a == b */ ;

void* if_branch[2];
if_branch[1] = &&ifcode;
if_branch[0] = &&elsecode;

goto if_branch[!!condition];

ifcode:
    /* code if (condition) is met */
    goto afterif;
elsecode:
    /* code if (condition) is not met */
afterif:

While convoluted, this shows that you can implement conditional branching without using if statements, ternary statements, or any other form of abuse other than goto pointers.

With conditional branching and goto (and all that other good stuff that doesn't require braces like addition, subtraction, etc.), you can build a machine language, and thereby implement all that other stuff that requires braces or "implied" braces, and could (theoretically, anyway) create any C program in this form without using more than one set of braces.

Answer 3

No braces

Doesn't answer the question, but does answer its title - C without braces

main=195;

Works on x86 (32bit and 64bit). Does nothing exciting, but starts and terminates without error.