/in/foo.c: In function 'main':
/in/foo.c:8:2: error: 'c' undeclared (first use in this function)
  c = a * b;
  ^
/in/foo.c:8:2: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:10:2: error: 'd' undeclared (first use in this function)
  d=c%2;
  ^
/in/foo.c:12:19: error: stray '\357' in program
   printf("Even\n")；
                   ^
/in/foo.c:12:20: error: stray '\274' in program
   printf("Even\n")；
                    ^
/in/foo.c:12:21: error: stray '\233' in program
   printf("Even\n")；
                     ^
/in/foo.c:13:2: error: expected ';' before 'else'
  else
  ^~~~
/in/foo.c:15:2: error: 'retuen' undeclared (first use in this function)
  retuen 0;
  ^~~~~~
/in/foo.c:15:9: error: expected ';' before numeric constant
  retuen 0;
         ^