View Compilation Error

0_0_25622382_28452.cpp: In function 'int main()':
0_0_25622382_28452.cpp:15:50: error: 'i' was not declared in this scope
   if(1<n&&s[1]=='?')if(s[0]=='0')s[1]='+';else s[i]='1';
                                                  ^