View Compilation Error

0_0_15802477_5760.cpp: In function 'int main(int, char**)':
0_0_15802477_5760.cpp:18:20: error: 'null' was not declared in this scope
    struct sicks *p=null;
                    ^
0_0_15802477_5760.cpp:28:13: error: 'doc' was not declared in this scope
      case 1:doc.push(sicks);
             ^
0_0_15802477_5760.cpp:28:27: error: expected primary-expression before ')' token
      case 1:doc.push(sicks);
                           ^
0_0_15802477_5760.cpp:29:27: error: expected primary-expression before ')' token
      case 2:doc.push(sicks);
                           ^
0_0_15802477_5760.cpp:30:27: error: expected primary-expression before ')' token
      case 3:doc.push(sicks);
                           ^