foo.c: In function ‘main’:
foo.c:6:9: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘scanf’
    6 |         scanf("%d%d%d",&a,&b,&c);
      |         ^~~~~
foo.c:10:17: error: ‘max’ undeclared (first use in this function)
   10 |                 max=a;
      |                 ^~~
foo.c:10:17: note: each undeclared identifier is reported only once for each function it appears in