For example, if test is a boolean variable, then. Any good programming language has some nifty little features that aren't really necessary but that let you feel cool when you use them. Java has the conditional operator. It's a ternary operator -- that is, it has three operands -- and it comes in two pieces,? It takes the form. The computer tests the value of boolean-expression. If the value is true , it evaluates expression-1 ; otherwise, it evaluates expression For example:.
So, if you want to assign the value of B to A and test at the same time whether that value is zero, you could say:. In general, the type of the expression on the right-hand side of an assignment statement must be the same as the type of the variable on the left-hand side. However, in some cases, the computer will automatically convert the value computed by the expression to match the type of the variable.
Consider the list of numeric types: byte , short , int , long , float , double. A value of a type that occurs earlier in this list can be converted automatically to a value that occurs later. The idea is that conversion should only be done automatically when it can be done without changing the semantics of the value.
Any int can be converted to a double with the same numeric value. However, there are int values that lie outside the legal range of short s. There is simply no way to represent the int as a short , for example, since the largest value of type short is In some cases, you might want to force a conversion that wouldn't be done automatically. For this, you could use what is called a type cast.
A type cast is indicated by putting a type name, in parentheses, in front of the value you want to convert. For example,. You can do type casts from any numeric type to any other numeric type. However, you should note that you might change the numeric value of a number by type-casting it. For example, short is The is obtained by taking the 4-byte int and throwing away two of those bytes to obtain a short -- you've lost the real information that was in those two bytes.
As another example of type casts, consider the problem of getting a random integer between 1 and 6. The function Math. A real number is cast to an integer by discarding the fractional part. You can also type-cast between the type char and the numeric types. The numeric value of a char is its Unicode code number. Java has several variations on the assignment operator, which exist to save typing.
Every operator in Java that applies to two operands gives rise to a similar assignment operator. If you use several operators in one expression, and if you don't use parentheses to explicitly indicate the order of evaluation, then you have to worry about the precedence rules that determine the order of evaluation.
Advice: don't confuse yourself or the reader of your program; use parentheses liberally. Here is a listing of the operators discussed in this section, listed in order from highest precedence evaluated first to lowest precedence evaluated last :. Operators on the same line have the same precedence.
When they occur together, unary operators and assignment operators are evaluated right-to-left, and the remaining operators are evaluated left-to-right. After the name of you variable, you can assign a value of either true or false. So the first IF Statement checks if the user variable has a value of true. The else part checks if it is false.
After all, if something is not true then it's false. So you can just use else: there's only two choices with boolean values. The only other conditional operator on our lists is the NOT operator. R Programming. React Native. Python Design Patterns.
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