Question

I have a question concerning floating constants in C.

In Java, the default type of floating point constants in double, so the following will causes a compilation error in java:

float f = 100.0;   // we either need to uses type case operator or put f at the end of the number constant.

This is because the default floating-point constants are of type double and casting from double to float without type cast operator is an error, so we need either add a type case operator or put f at the end of the number.

So, Why in C this doesn’t produce an error, Is it because the default floating-point constants are of type float, or because the compiler do an implicit down-cast conversion (that doesn’t requires type case operator in C)????

Answer 1

In C, floating point constants have type double by default, but a double can be implicitly converted to a float (note that you do have to be careful: if the value of the constant is outside the range representable by a float, the result of such a conversion is undefined).

If you want a floating point constant of type float, you can append the suffix f to the end of the constant.