/in/foo.cc: In function 'int main()':
/in/foo.cc:8:9: warning: 's1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   zs+=s1*s2*s2*3.14159;
       ~~^~~
/in/foo.cc:8:9: warning: 's2' may be used uninitialized in this function [-Wmaybe-uninitialized]
/in/foo.cc:11:10: warning: 'cs' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<cs;
          ^
/in/foo.cc:8:16: warning: 'zs' may be used uninitialized in this function [-Wmaybe-uninitialized]
   zs+=s1*s2*s2*3.14159;
                ^~~~~~~