View Compilation Error

0_0_18493071_9886.cpp: In function 'int main()':
0_0_18493071_9886.cpp:55:22: error: 'a' was not declared in this scope
      scanf("%d%d%d",&a,&b,&t);  
                      ^
0_0_18493071_9886.cpp:55:25: error: 'b' was not declared in this scope
      scanf("%d%d%d",&a,&b,&t);  
                         ^
0_0_18493071_9886.cpp:55:28: error: 't' was not declared in this scope
      scanf("%d%d%d",&a,&b,&t);  
                            ^