View Compilation Error

0_0_36140938_18179.cpp: In function 'int main()':
0_0_36140938_18179.cpp:4:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&n)!=EOF){
                     ^
0_0_36140938_18179.cpp:4:24: error: 'EOF' was not declared in this scope
  while(scanf("%d",&n)!=EOF){
                        ^
0_0_36140938_18179.cpp:24:22: error: 'printf' was not declared in this scope
   printf("%d\n",c1[n]);
                      ^