View Compilation Error

0_0_30256746_3719.cpp: In function 'int main()':
0_0_30256746_3719.cpp:3:19: error: 'scanf' was not declared in this scope
     scanf("%d", &t);
                   ^
0_0_30256746_3719.cpp:7:45: error: 'printf' was not declared in this scope
         printf("%lld", (m/(n-k+1))*(k-1)+m+1);
                                             ^