运行 ID: 51232

Main.cc: In function ‘int main()’:
Main.cc:5:18: error: ‘m’ was not declared in this scope
     for (int i = m;i>=n;i-=2){
                  ^
Main.cc:5:23: error: ‘n’ was not declared in this scope
     for (int i = m;i>=n;i-=2){
                       ^
Main.cc:11:13: error: ‘n’ was not declared in this scope
     cout << n*(n+1)/2;
             ^