View Compilation Error

0_0_36213120_18135.cpp: In function 'int main()':
0_0_36213120_18135.cpp:26:15: error: 'A' was not declared in this scope
  while(cin >> A >> B >> C){
               ^
0_0_36213120_18135.cpp:26:20: error: 'B' was not declared in this scope
  while(cin >> A >> B >> C){
                    ^
0_0_36213120_18135.cpp:26:25: error: 'C' was not declared in this scope
  while(cin >> A >> B >> C){
                         ^