#ifndef

[Filorn]

There are two errors at the lines 3 and 4:
expected '}' at the end of input
unterminated #ifndef

#include <stdio.h>
#define NUMERO 4
int main(void){
#ifndef NUMERO
#define NUMBER 4
#ifdef NUMBER
#undef NUMBER
#define NUMERO 4
#endif
return 0;
}

[booradley60]

The #ifndef on line 4 has no corresponding #endif. But what on earth are you trying to accomplish with this?

[appi]

were u wanted to do this thing ??

#include <stdio.h>
#define NUMERO 4
int main(void){
#if NUMERO
#define NUMBER 4
#if NUMBER
#endif
#define NUMERO 4
#endif
return 0;
}