CODEWITHSUNDEEP
cvisual-c++visual-studio-2012
Ivan Akulov
Ivan Akulov

Reputation: 4323

Can't define variables after a function call

I have a great experience of C++, and now I'm trying to do some things in pure C. But I noticed a really strange fact.

The following code:

#include <stdio.h>

int main()
{
    double a;
    scanf_s("%lf", &a);

    double b;
    b = a + 1;

    printf("%lf", b);

    return 0;
}

compiles OK in sourceLair (with gcc compiler, as well as I know), but generates following errors in Microsoft Visual Studio (with Visual C++):

1>Task 1.c(8): error C2143: syntax error : missing ';' before 'type'
1>Task 1.c(9): error C2065: b: undeclared identifier
1>Task 1.c(9): warning C4244: =: conversion from 'double' to 'int', possible loss of data
1>Task 1.c(11): error C2065: b: undeclared identifier

I experimented a bit with the code and noticed that placing a variable declaration before calling any function is OK, but placing a declaration after it results in compilation error.

So what's wrong? I use a fresh installation of Microsoft Visual Studio 2012 Express with no settings changed.

Upvotes: 1

Views: 668

Answers (1)

user529758
user529758

Reputation:

Assuming that this is being compiled as C, I have bad news for you: Microsoft's compiler that comes with Visual Studio does not support C99, only C89, and in that revision of the language, one can only declare variables at the beginning of a scope. A declaration after a non-declaration statement is an error.

So, either rewrite your code so that it conforms to C89, or use a compiler that supports C99 (such as GCC, that can be used after installing MinGW, or clang, which only has experimental support for integration with VS).

Upvotes: 4

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