/in/foo.cc: In function 'int main()':
/in/foo.cc:33:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                     for(int i=0;i<s1.length();i++)
                                  ^
/in/foo.cc:35:37: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
                         if(s1[i]>'a'&&s1[i]<'z'||s1[i]>'A'&&s1[i]<'Z')
                                     ^
/in/foo.cc:45:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                     for(int i=0;i<s1.length();i++)
                                  ^
/in/foo.cc:47:37: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
                         if(s1[i]>'a'&&s1[i]<'z'||s1[i]>'A'&&s1[i]<'Z')
                                     ^