/in/foo.c: In function 'main':
/in/foo.c:4:2: warning: implicit declaration of function 'sanf' [-Wimplicit-function-declaration]
  sanf("%d%d%d",&a,&b,&c);
  ^~~~
/in/foo.c:8:2: error: 'else' without a previous 'if'
  else a=a+b;
  ^~~~
/in/foo.c:14:2: error: 'else' without a previous 'if'
  else a=a+c;
  ^~~~