View Compilation Error

0_0_20981028_19912.cpp: In function 'int main()':
0_0_20981028_19912.cpp:52:25: error: 'scanf' was not declared in this scope
     while(scanf("%d", &n) != EOF) {
                         ^
0_0_20981028_19912.cpp:52:30: error: 'EOF' was not declared in this scope
     while(scanf("%d", &n) != EOF) {
                              ^
0_0_20981028_19912.cpp:63:22: error: 'sort' was not declared in this scope
         sort(S, S + m);
                      ^
0_0_20981028_19912.cpp:69:39: error: 'memset' was not declared in this scope
         memset(cover, 0, sizeof(cover));
                                       ^
0_0_20981028_19912.cpp:78:76: error: 'printf' was not declared in this scope
         printf("Test case #%d\nTotal explored area: %.2lf\n\n", cas ++, ans);
                                                                            ^