运行 ID: 44642

Main.cc:5:1: error: expected initializer before ‘int’
 int i,j;
 ^~~
Main.cc: In function ‘int main()’:
Main.cc:8:7: error: ‘a’ was not declared in this scope
  cin>>a;
       ^
Main.cc:10:2: error: ‘i’ was not declared in this scope
  i=0;
  ^
Main.cc:11:2: error: ‘j’ was not declared in this scope
  j=len-1;
  ^