Bug with my compiler? Two equal code files, but only one of those works

Question

I've been learning C++, and I was just starting with C, but I got this weird problem which was stopping my compiler from compiling. There were several stray '\342' and whatever errors.

Well, I now know that those are caused by using non-ASCII characters, but the solution to the rest of the posts were very simple. They were using different "" signs because they got the code through copy paste.

I just wrote both this "int main"s (I commented one block or another to test the code... also don't mind the Portuguese. It isn't relevant at all):

#include <stdio.h>
#include <stdlib.h>

/*
int main()
{
    float x;
    printf("Introduza um numero com bastantes casas decimais: \n");
    scanf("%f", &x);
    printf("Com 2 casas decimais: %.2f  \nCom todas as casas decimais %f", x, x);⁠⁠⁠⁠
    return 0;
}

*/

int main()
{
    float var;

    printf("Introduza um numero com bastantes casas decimais: \n");

    scanf("%f", &var);

    printf("Com 2 casas decimais: %.2f \nCom todas as casas decimais: %f", var, var);


}

The first block doesn't work, it gives me this errors:

||=== Build: Debug in ExplicAna (compiler: GNU GCC Compiler) ===|
/home/meneses/Cê/ExplicAna/main.c||In function ‘main’:|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\342’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\201’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\240’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\342’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\201’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\240’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\342’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\201’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\240’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\342’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\201’ in program|
/home/meneses/Cê/ExplicAna/main.c|10|error: stray ‘\240’ in program|

on this line:

printf("Com 2 casas decimais: %f  \nCom todas as casas decimais %f", x, x);⁠⁠⁠⁠

I erased that line three times, rewrote it, but nothing. The " looks exactly the same.

I then wrote the other code which is the exactly equal and to my surprise it worked!

What am I missing?

I'm worried because this is my first time compiling C and am afraid it might cause harm again in the future.

Answer 1

After fixing the var to be x in both code lines, the second code (working) line ends with the following octets:

 x  , sp  x  )  ; lf
78 2c 20 78 29 3b 0a

However the first one (broken) ends with:

 x  , sp  x  )  ;                                     lf
78 2c 20 78 29 3b e2 81 a0 e2 81 a0 e2 81 a0 e2 81 a0 0a

in other words, sandwiched between the semicolon and the linefeed you have:

e2 81 a0 e2 81 a0 e2 81 a0 e2 81 a0

You indeed have hidden characters in your first code line after the semi-colon, but before the linefeed, which your compiler is rightly bitching about.