/in/foo.cc: In function 'int main()':
/in/foo.cc:15:48: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if((a[i]<=a[i-1]&&a[i]<=a[i+1])||a[i]>=a[i-1]&&a[i]>=a[i+1])
                                    ~~~~~~~~~~~~^~~~~~~~~~~~~~
/in/foo.cc:15:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if((a[i]<=a[i-1]&&a[i]<=a[i+1])||a[i]>=a[i-1]&&a[i]>=a[i+1])
     ^