View Compilation Error

0_0_30868087_26041.cpp: In function 'int main()':
0_0_30868087_26041.cpp:4:16: error: 'a' was not declared in this scope
  scanf("%d%d",&a,&b);
                ^
0_0_30868087_26041.cpp:4:19: error: 'b' was not declared in this scope
  scanf("%d%d",&a,&b);
                   ^