View Compilation Error

0_0_21044490_4042.cpp: In function 'int main()':
0_0_21044490_4042.cpp:4:24: error: 'scanf' was not declared in this scope
   int t; scanf("%d", &t);
                        ^
0_0_21044490_4042.cpp:9:26: error: 'n' was not declared in this scope
     for (int i = 1; i <= n; ++i) {
                          ^