Funny little thing...

[Adrian Yan]

Just realize that float f = 1.0; will not compile.

[Edy Yu]

of cours eit can't cus 1.0 is double. you have to explicitly convert it to float.

[bill bozeman]

Any number with a decimal point is a double by default. So when you are saying float f = 1.0 you are saying float f = 1.0d. If you say float f = 1.0f, you are telling the compiler that 1.0 is a float so you are ok.

[Hemal Mehta]

Just remeer the rulethat only widening conversion is allowed.
The following may be remembered:
byte-short(char also same) -int-long-float-double

[Bharatesh H Kakamari]

float f = 4;
will compile as 4 is considered int by the compiler. Hence conversion from int to float (widening) is allowed. But float f =4.0 is not allowed as any number with decimal point is considered as double. Hence explicit cast is required or float f = 4.0f should be provided.