View Compilation Error

0_0_37536695_23452.cpp: In function 'int main()':
0_0_37536695_23452.cpp:4:24: error: 'scanf' was not declared in this scope
     while(scanf("%d",&n)!=EOF) 
                        ^
0_0_37536695_23452.cpp:4:27: error: 'EOF' was not declared in this scope
     while(scanf("%d",&n)!=EOF) 
                           ^
0_0_37536695_23452.cpp:6:37: error: 'printf' was not declared in this scope
         printf("%.f\n\n",(1+n)/2.0*n); 
                                     ^