Why the error of - calling the function before being declared, is not shown?

Question

main()
{
    f();
}
int f( int i, float fl)
{
    printf(\"function\");
}

1. Why does the above code runs successfully in \'C\' and prints

Answer 1

The error does not show in C because you're not using the proper flags in the invocation of your compiler.

What is your compiler?

If it's gcc, try gcc -std=c99 -pedantic -Werror ...