View Compilation Error

0_0_21642814_6541.cpp: In function 'int main()':
0_0_21642814_6541.cpp:7:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&n),n){
                     ^
0_0_21642814_6541.cpp:9:7: error: 'i' was not declared in this scope
   rep(i,n)scanf("%s",in[i]);
       ^
0_0_21642814_6541.cpp:9:10: error: 'rep' was not declared in this scope
   rep(i,n)scanf("%s",in[i]);
          ^
0_0_21642814_6541.cpp:11:21: error: 'strlen' was not declared in this scope
   for(i=strlen(in[0])-1;i>=0;i--){
                     ^
0_0_21642814_6541.cpp:34:26: error: 'printf' was not declared in this scope
   printf("Case %d: ",++cs);
                          ^
0_0_21642814_6541.cpp:35:25: error: 'puts' was not declared in this scope
   if(m>9999)puts("error");
                         ^