View Compilation Error

0_0_34661081_29695.cpp: In function 'int main()':
0_0_34661081_29695.cpp:19:25: error: 'scanf' was not declared in this scope
     while(scanf("%d", &n) != EOF) {
                         ^
0_0_34661081_29695.cpp:19:30: error: 'EOF' was not declared in this scope
     while(scanf("%d", &n) != EOF) {
                              ^
0_0_34661081_29695.cpp:29:48: error: 'qsort' was not declared in this scope
         qsort(record, n, sizeof(record[0]), cmp);
                                                ^
0_0_34661081_29695.cpp:42:29: error: 'printf' was not declared in this scope
         printf("%d\n", count);
                             ^