/in/foo.c: In function 'main':
/in/foo.c:6:18: error: 'a' undeclared (first use in this function)
    6 |     scanf("%f", &a);
      |                  ^
/in/foo.c:6:18: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:8:18: error: 'b' undeclared (first use in this function)
    8 |     scanf("%f", &b);
      |                  ^
/in/foo.c:10:18: error: 'c' undeclared (first use in this function)
   10 |     scanf("%f", &c);
      |                  ^
/in/foo.c:4:17: warning: unused variable 'z' [-Wunused-variable]
    4 |         int x,y,z;
      |                 ^
/in/foo.c:4:15: warning: unused variable 'y' [-Wunused-variable]
    4 |         int x,y,z;
      |               ^
/in/foo.c:4:13: warning: unused variable 'x' [-Wunused-variable]
    4 |         int x,y,z;
      |             ^