View Compilation Error

0_0_17513234_21492.cpp: In function 'int main()':
0_0_17513234_21492.cpp:5:32: error: 'scanf' was not declared in this scope
     while (scanf("%d%d", &n, &m) != EOF)
                                ^
0_0_17513234_21492.cpp:5:37: error: 'EOF' was not declared in this scope
     while (scanf("%d%d", &n, &m) != EOF)
                                     ^
0_0_17513234_21492.cpp:11:49: error: 'printf' was not declared in this scope
             printf(c++ ? " %d" : "%d", b + m - 1);//输出改组的平均数
                                                 ^
0_0_17513234_21492.cpp:14:53: error: 'printf' was not declared in this scope
         printf(n % m ? " %d\n" : "\n", b + n % m - 1);//最后不足m个，则以实际数量求平均值
                                                     ^