/in/foo.cc: In function 'int main()':
/in/foo.cc:19:11: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if(a[i]>=400&a[i]<=799)
       ~~~~^~~~~
/in/foo.cc:21:11: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if(a[i]>=800&a[i]<=1199)
       ~~~~^~~~~
/in/foo.cc:23:11: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if(a[i]>=1200&a[i]<=1599)
       ~~~~^~~~~~
/in/foo.cc:25:11: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if(a[i]>=1600&a[i]<=1999)
       ~~~~^~~~~~
/in/foo.cc:27:11: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if(a[i]>=2000&a[i]<=2399)
       ~~~~^~~~~~
/in/foo.cc:29:11: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if(a[i]>=2400&a[i]<=2799)
       ~~~~^~~~~~
/in/foo.cc:31:11: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if(a[i]>=2800&a[i]<=3199)
       ~~~~^~~~~~