foo.c: In function 'main':
foo.c:5:9: warning: right-hand operand of comma expression has no effect [-Wunused-value]
    5 |  for(n=2,n<a,n++)
      |         ^
foo.c:5:17: error: expected ';' before ')' token
    5 |  for(n=2,n<a,n++)
      |                 ^
      |                 ;
foo.c:5:17: error: expected expression before ')' token
foo.c:9:11: warning: statement with no effect [-Wunused-value]
    9 |           n
      |           ^
foo.c:9:12: error: expected ';' before '}' token
    9 |           n
      |            ^
      |            ;
   10 |   }
      |   ~         
foo.c:14:22: error: expected ';' before 'return'
   14 |          printf("no")
      |                      ^
      |                      ;
......
   17 | return 0;
      | ~~~~~~                

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