/in/foo.c: In function 'main':
/in/foo.c:6:2: error: 'intPI' undeclared (first use in this function)
  intPI=3.14159;
  ^~~~~
/in/foo.c:6:2: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:7:3: error: 'S' undeclared (first use in this function)
   S=PI*squrt A*b;
   ^
/in/foo.c:7:5: error: 'PI' undeclared (first use in this function)
   S=PI*squrt A*b;
     ^~
/in/foo.c:7:8: error: 'squrt' undeclared (first use in this function)
   S=PI*squrt A*b;
        ^~~~~
/in/foo.c:7:14: error: expected ';' before 'A'
   S=PI*squrt A*b;
              ^
/in/foo.c:8:10: warning: missing terminating " character
   printf("%.2/d,S);
          ^
/in/foo.c:8:10: error: missing terminating " character
   printf("%.2/d,S);
          ^~~~~~~~~~
/in/foo.c:9:2: error: expected expression before 'return'
  return 0;
  ^~~~~~
/in/foo.c:10:7: error: expected ';' before '}' token
       }
       ^