View Compilation Error

0_0_25076338_14157.cpp: In function 'int main()':
0_0_25076338_14157.cpp:5:17: error: 'scanf' was not declared in this scope
    scanf("%d",&N);
                 ^
0_0_25076338_14157.cpp:6:12: error: 'getchar' was not declared in this scope
    getchar();
            ^
0_0_25076338_14157.cpp:10:16: error: 'gets' was not declared in this scope
        gets(str);
                ^
0_0_25076338_14157.cpp:17:26: error: 'printf' was not declared in this scope
         printf("%d\n",sum);
                          ^