View Compilation Error

0_0_30425418_12788.cpp: In function 'int main()':
0_0_30425418_12788.cpp:15:16: error: 's' was not declared in this scope
             if(s[i]=='z')
                ^
0_0_30425418_12788.cpp:18:15: error: 's' was not declared in this scope
         cout<<s<<endl;
               ^