View Compilation Error

0_0_22099642_5462.cpp: In function 'int main()':
0_0_22099642_5462.cpp:4:25: error: 'scanf' was not declared in this scope
     while(~scanf("%d",&n)){  
                         ^
0_0_22099642_5462.cpp:20:28: error: 'printf' was not declared in this scope
         printf("%d\n",t+5*k);  
                            ^