View Compilation Error

0_0_37212505_14148.cpp: In function 'int main()':
0_0_37212505_14148.cpp:33:24: error: 'scanf' was not declared in this scope
     while(scanf("%d",&n)!=EOF)
                        ^
0_0_37212505_14148.cpp:33:27: error: 'EOF' was not declared in this scope
     while(scanf("%d",&n)!=EOF)
                           ^
0_0_37212505_14148.cpp:35:29: error: 'memset' was not declared in this scope
         memset(g,0,sizeof(g));
                             ^
0_0_37212505_14148.cpp:41:13: error: 'cin' was not declared in this scope
             cin>>i>>a;
             ^
0_0_37212505_14148.cpp:52:13: error: 'cout' was not declared in this scope
             cout<<1<<endl;
             ^
0_0_37212505_14148.cpp:52:22: error: 'endl' was not declared in this scope
             cout<<1<<endl;
                      ^
0_0_37212505_14148.cpp:61:9: error: 'cout' was not declared in this scope
         cout<<res/2<<endl;
         ^
0_0_37212505_14148.cpp:61:22: error: 'endl' was not declared in this scope
         cout<<res/2<<endl;
                      ^