Created: 2022-08-19
Tags: #fleeting
When an operator has operands of different types,
they are converted to a common type according to a small number of rules.
In general, the only automatic conversions are
those that convert a narrower operand into a wider one without losing information,
such as converting an integer into floating point in an expression like f + i.
Expressions that don't make sense, like using a float as a subscript, are disallowed. Expressions that might lose information,
like assigning a longer integer type to a shorter, or
a floating-point type to an integer,
may draw a warning, but they are not illegal.
A char is just a small integer, so chars may be freely used in arithmetic expressions
There is one subtle point about the conversion of char to int.
The language does not specify whether variables of type char are signed or unsigned
When char is converted to int, can it ever produce a negative integer?
The answer varies from machine to machine, reflecting differences in architecture.
IF -> NONchar data (bit) is to be stored in char variables
THEN -> specify if its signed or unsigned
WHY -> Because arbitrary bit patterns stored in character variables may appear to be negative on some machines, yet positive on others.
Automatic Conversion Rules in Arithmetic Expressions
The highest data type the expression has will convert every data type into that same highest data type. For instance, if we have at least double with the remaining operands as int and float, then those int/float operands will be automatically conversed into double.
Conversions take place across assignments; the value of the right side is converted to the type of the left, which is the type of the result.
Thoughts -> So you mean that 1 == 1.0 won't be converted to 1 == 1 ???? Because like it siad, the right side will convert to whatever is on the left side. Since left side is int, it is lower than float. Oh actually, that type of conversion permits it, only there is a warning invovled that information will be lost along the way.
Final Answer -> It is possible for 1 == 1.0 to be converted to both int 1 == 1 but we just lose an information of the decimal place.
So, it's not only in arithmetic expressions but it also happens with logical operations
1.0 == 1 -> 1.0 == 1.0
Thoughts -> When you think about it, it does make sense
because if you compare a floating 1.0 to int 1, technically they are different numbers so the automatic conversion rules actually make sense here.
type conversion also takes place when arguments are passed to functions