View Compilation Error

0_0_19100361_5764.cpp:1:14: error: 'N' was not declared in this scope
 char table_a[N] = {};
              ^
0_0_19100361_5764.cpp:2:14: error: 'N' was not declared in this scope
 char table_b[N] = {};
              ^
0_0_19100361_5764.cpp: In function 'int main()':
0_0_19100361_5764.cpp:8:24: error: 'scanf' was not declared in this scope
  while (~scanf("%d", &m))
                        ^
0_0_19100361_5764.cpp:13:12: error: 'getchar' was not declared in this scope
    getchar();//吸收空格
            ^
0_0_19100361_5764.cpp:18:30: error: 'printf' was not declared in this scope
    printf("%.lf\n", count / 2);
                              ^