foo.cc: In function 'int main()':
foo.cc:8:19: error: 'i' was not declared in this scope
     for(int t=0;s[i]!=0;i++){
                   ^
foo.cc:8:13: warning: unused variable 't' [-Wunused-variable]
     for(int t=0;s[i]!=0;i++){
             ^

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。