foo.cc: In function ‘bool n(int)’:
foo.cc:5:18: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
    5 |         if(a%4==0&&a%100!=0||a%400==0) return 1;return 0;}
      |            ~~~~~~^~~~~~~~~~
foo.cc:5:9: warning: this ‘if’ clause does not guard... [-Wmisleading-indentation]
    5 |         if(a%4==0&&a%100!=0||a%400==0) return 1;return 0;}
      |         ^~
foo.cc:5:49: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the ‘if’
    5 |         if(a%4==0&&a%100!=0||a%400==0) return 1;return 0;}
      |                                                 ^~~~~~