Код Netbeans по умолчанию становится серым

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#else

static double prev_value = 0.0;    // this lines becomes grey

// CLOCK_MONOTONIC represents the absolute elapsed wall-clock time 
//since 
// some arbitrary, fixed point in the past. It isn't affected by 
//changes in 
// the system time-of-day clock.

int r = clock_gettime( CLOCK_MONOTONIC, &t );   // this line also 
 // become grey  

#endif   

if ( r < 0 ) 
{
    // gettime can fail, so we need to do a check and possibly 
    //print error

    fprintf(stderr, "%s\n", strerror(errno)); 


 // On error return previous time


    return prev_value;   // Compiler throws an error that it could not 
                         // resolve the identifier prev_value 

}
The link of the image is this : https://1drv.ms/u/s!AmyCvVHlJ4uYgmyRyBji-3Njj6t9

Please someone help.

Что я уже пробовал:

Я использую NetBeans версии 8.2. Я использую некоторые код на C в ней.

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