View Compilation Error

0_0_20128818_21558.cpp: In function 'int main()':
0_0_20128818_21558.cpp:6:12: error: 'a' was not declared in this scope
 while(cin>>a>>b>>c)
            ^
0_0_20128818_21558.cpp:6:15: error: 'b' was not declared in this scope
 while(cin>>a>>b>>c)
               ^
0_0_20128818_21558.cpp:6:18: error: 'c' was not declared in this scope
 while(cin>>a>>b>>c)
                  ^