foo.cc: In function 'bool cmp()':
foo.cc:14:5: warning: unused variable 'f' [-Wunused-variable]
 int f=1;
     ^
foo.cc: At global scope:
foo.cc:74:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^
foo.cc: In function 'bool cmp()':
foo.cc:28:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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