View Compilation Error

0_0_25091241_1325.cpp: In function 'int main()':
0_0_25091241_1325.cpp:22:20: error: 'scanf' was not declared in this scope
 scanf("%d %d",&h,&w);
                    ^
0_0_25091241_1325.cpp:25:9: error: 'getchar' was not declared in this scope
 getchar();
         ^
0_0_25091241_1325.cpp:43:18: error: 'printf' was not declared in this scope
 printf("%d\n",max);
                  ^