How to find missing "?

[Andy Jackman]

Hi,
When compiling a C program I get an error: 

test.c:1047:65: missing terminating " character. 

I know what this is - I've left a " out in a string literal somewhere
(not on line 1047 where the last " in my program appears), but I'm not
clever enough to find it in 1000 lines of code (using vi) without
searching for every " and then manually inspecting the line. I've
started doing that, but I figure someone has a better way to find a line
that contains only one " (since this is likely to be where the error
is).

Any ideas gratefully received,
Thanks,
Andy.