1 2 extern void abort (); 3 extern void exit (int); 4 f(int a)5 int f (int a) { 6 if (a != 2) { 7 a = -a; 8 if (a == 2) 9 return 0; 10 return 1; 11 } 12 return 1; 13 } 14 main(int argc,char * argv[])15 int main (int argc, char *argv[]) { 16 if (f (-2)) 17 abort (); 18 exit (0); 19 } 20 21