foo.cc:3:20: error: ISO C++ forbids declaration of 'isLeapYear' with no type [-fpermissive]
    3 | isLeapYear(int year)
      |                    ^
foo.cc: In function 'int daysOfMonth(int, int)':
foo.cc:13:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   13 |   if(i==4||i==6||i==9||i==11)t+=30;i++;
      |   ^~
foo.cc:13:36: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   13 |   if(i==4||i==6||i==9||i==11)t+=30;i++;
      |                                    ^

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