Why object file size changes for the same code in C and C++

Question

I have written same lines of code in both C and C++ build environment of visual studio 2008 but C code's object file size is 5.5kb and C++ code file size is 6.17 kb. Why is this difference?

Following is the code in both environments:

#include <stdio.h>

struct S
{
    char c;
};
void func()
{
    int i;
    int j;
    printf("%d", i);
}

int main()
{
    struct S s;
    return 0;
}

Answer 1

It links different C runtime libraries in each case. Check here for detailed explanation. For instance, libcmt.lib vs libcpmt.lib.

Answer 2

Just because your code has different meaning in C and C++.

• In C++ you declare functions that receive no arguments, in C you declare functions that have an unspecified number of arguments. (Never change the signature of main)
• function names are mangled in C++
• functions may throw exceptions in C++
• executables are linked against different libraries by default
• because of the lack of initialization of i the call to printf has undefined behavior. Both languages might decide on different strategies to shoot you.