/in/foo.c: In function 'main':
/in/foo.c:5:10: warning: statement with no effect [-Wunused-value]
    5 |         n>3;
      |         ~^~
/in/foo.c:8:20: error: 'o' undeclared (first use in this function)
    8 |         {  if(n%i==o)
      |                    ^
/in/foo.c:8:20: note: each undeclared identifier is reported only once for each function it appears in