View Compilation Error

0_0_36774866_4029.cpp: In function 'int main()':
0_0_36774866_4029.cpp:7:18: error: 'scanf' was not declared in this scope
     scanf("%d",&t);
                  ^
0_0_36774866_4029.cpp:10:9: error: 'm' was not declared in this scope
         m=n*log10(n);
         ^
0_0_36774866_4029.cpp:12:41: error: 'printf' was not declared in this scope
         printf("%d\n",(int)pow(10.0,dec));//10^dec
                                         ^