View Compilation Error

0_0_26601509_8288.cpp: In function 'int main()':
0_0_26601509_8288.cpp:4:2: error: 'duoble' was not declared in this scope
  duoble a,b;
  ^
0_0_26601509_8288.cpp:5:19: error: 'a' was not declared in this scope
  scanf("%lf %lf",&a,&b);
                   ^
0_0_26601509_8288.cpp:5:22: error: 'b' was not declared in this scope
  scanf("%lf %lf",&a,&b);
                      ^