/in/foo.c: In function 'main':
/in/foo.c:6:10: warning: format '%i' expects argument of type 'int *', but argument 2 has type 'double *' [-Wformat=]
  scanf("%if%if%if", &a, &b, &c);
          ^
/in/foo.c:6:13: warning: format '%i' expects argument of type 'int *', but argument 3 has type 'double *' [-Wformat=]
  scanf("%if%if%if", &a, &b, &c);
             ^
/in/foo.c:6:16: warning: format '%i' expects argument of type 'int *', but argument 4 has type 'double *' [-Wformat=]
  scanf("%if%if%if", &a, &b, &c);
                ^
/in/foo.c:11:2: warning: implicit declaration of function 'prinf' [-Wimplicit-function-declaration]
  prinf("x1=%7.2if\nx2=%7.2if", x1, x2);
  ^~~~~
/in/foo.c:5:16: warning: variable 'disc' set but not used [-Wunused-but-set-variable]
  double a,b,c, disc, x1, x2, p, q;
                ^~~~
/in/foo.c:9:5: warning: 'q' is used uninitialized in this function [-Wuninitialized]
  x1 = p + q;
  ~~~^~~~~~~
/tmp/ccRdwPR8.o: In function `main':
foo.c:(.text.startup+0x5a): undefined reference to `prinf'
collect2: error: ld returned 1 exit status