C - While loop before variables not compiling [duplicate]

Question

This question already has answers here:

error C2143: syntax error : missing ';' before 'type' (3 answers)

Closed 9 years ago.

I'm trying to make a loop in the main method in C, and it's not compiling.

Here's the code:

    int i = 1;
    while (i < 10) 
    {
        i++;
    }
    int x;
    int a;
    int b;
    int sum;
    sum = a + b;

It doesn't compile because this error:

Error   3   error C2143: syntax error : missing ';' before 'type'

This error appears in all the variables that are declared after the loop.

But, if I write the loop after these variable declaration, it works just fine.

So why can't I write a loop before variable declaration?

Answer 1

In C89 all variables should be declared at the top of a code block i.e. directly after a {, they don't have to be declared at the top of a function. In C99 and later they can be declared anywhere. If you have a section of code in your function that needs to use a set of variables that the rest of the function doesn't you can wrap this section in a block {...}`.

Answer 2

This is the typical response of an outdated Microsoft Visual C compiler which does not support the latest C standard. Seems they've got stuck in time.

Just move the variables before the loop and all should be fine.