View Compilation Error

0_0_19814848_27111.cpp: In function 'int main()':
0_0_19814848_27111.cpp:10:35: error: 'memset' was not declared in this scope
         memset(flag,0,sizeof(flag));//初始化，全部标为0 
                                   ^
0_0_19814848_27111.cpp: At global scope:
0_0_19814848_27111.cpp:42:2: error: expected unqualified-id before '/' token
 */  
  ^
0_0_19814848_27111.cpp:42:2: error: expected constructor, destructor, or type conversion before '/' token
0_0_19814848_27111.cpp: In function 'int main()':
0_0_19814848_27111.cpp:49:5: error: redefinition of 'int main()'
 int main()  
     ^
0_0_19814848_27111.cpp:4:5: note: 'int main()' previously defined here
 int main() 
     ^