"double type" query in c++

[ashjas]

Hi,

in c++ following code produces output as 1 how if i am using d as double?

double d=9/7;
cout<<"\n"<<d;

when i changed d=9/7 to d=9.0/7.0 it showed correct answer with all decimals..

Is it a rule that for using double we have to assign it a value that has a decimal otherwise it would consider it as an int?

Thanks.

[Laharl]

The value 7 is an integer. 7.0 is a decimal number, and thus would be treated as a float/double. To get division to work properly, you have to be careful to use the proper format.

[weaknessforcats]

9/7 is integer division. 7 divides into 9 once. Hence 1.

You assign the 1 to a double. This forces a conversion from int to double so your see 1.0.

by using 9.0/7.0 you define the values as double. Then you assign to a double.

Symbolic constants, like 9.0, are double. If you assign one of these to float (which is smaller), you will get a truncation and possible loss of data warning.

To assign to a float define your constant as a float: 9.0f ot 9.0F.