Need help to insert some text to my c++ file - bash

Question

I want to insert some text to my c++ file after certain line ( pattern ). The following is my file structure.
38 #include "stdlib.h"
39 #include "string.h"
40 #include "malloc.h"
41
...
324 void DMProcMon::threadManagerMonitorThread(DMProcMon* dmProcMon)
325 {
...
338 while (dmState == DVProcMon::Active &&
339 DmManService::getDCMRestartingFlag() == 0){
340 try{
342 setupTimerVerification(dmProcMon);
343 setupSignalVerification(dmProcMon);
344
....
360 }
I want to add code coverage macros using gcov. So basically what I need to achieve is
Add below text after all the #include statements.
45 #ifdef GCOV
46 extern "C"
47 void _gcov_flush();
48 #endif
Add the below text after the while statement in the threadManagerMonitorThread function
#ifdef GCOV
_gcov_flush();
#endif
So final code will loos like as below.
38 #include "stdlib.h"
39 #include "string.h"
40 #include "malloc.h"
41
45 #ifdef GCOV
46 _gcov_flush();
47 #endif
...
324 void DMProcMon::threadManagerMonitorThread(DMProcMon* dmProcMon)
325 {
...
338 while (dmState == DVProcMon::Active &&
339 DmManService::getDCMRestartingFlag() == 0){
340 try{
342 #ifdef GCOV
343 _gcov_flush();
344 #endif
346 setupTimerVerification(dmProcMon);
347 setupSignalVerification(dmProcMon);
348
....
360 }
What is the best way to do this. I would like to do this with either bash or pythyon.
Thanks
~S

Answer 1

You might use sed to insert a line after/before a line containing a certain pattern. See this: https://stackoverflow.com/a/11695086/2749648.
Also here is the explanation on how to insert a line after a block of code (this will help you with the #include block) but i am not sure on how to fix the while statement. If while statement is on a single line, it would be easy, but that is hard to guarantee.