Why doesn't the compiler report a missing semicolon?

Question

I have this simple program:

#include 

struct S
{
    int i;
};

void swap(struct S *a, struct S *b)
{
    struct S temp;
    temp = *a    /*          


        

Answer 1

Most compilers parse source files in order, and report the line where they discover that something was wrong. The first 12 lines of your C program could be the start of a valid (error-free) C program. The first 13 lines of your program cannot. Some compilers will note the location of things they encounter which are not errors in and of themselves, and in most cases won't trigger errors later in the code, but might not be valid in combination with something else. For example:

int foo;
...
float foo;

The declaration int foo; by itself would be perfectly fine. Likewise the declaration float foo;. Some compilers may record the line number where the first declaration appeared, and associate an informational message with that line, to help the programmer identify cases where the earlier definition is actually the erroneous one. Compilers may also keep the line numbers associated with something like a do, which can be reported if the associated while does not appear in the right place. For cases where the likely location of the problem would be immediately preceding the line where the error is discovered, however, compilers generally don't bother adding an extra report for the position.