Placeholder Image

字幕表 動画を再生する

  • The numerical operators in C++ can be grouped into five types: arithmetic, assignment, comparison,

  • logical, and bitwise operators.

  • First, we have the four basic arithmetic operations, as well as modulus to get the division remainder.

  • Notice that the division sign gives an incorrect result here. This is because it operates on

  • two integer values and will therefore trunctate the result and return an integer. To get the

  • correct value we need to explicitly convert one of the numbers to a floating-point number.

  • A common use of the assignment and arithmetic operators is to operate on a variable and

  • then to save the result back into that same variable. These operations can be shortened

  • with the combined assignement operators.

  • Another common operation is to increment or decrement a variable by one.

  • This can be simplified with the increment (++) and decrement (--) operators.

  • Both of these can either be used before or after a variable.

  • The result on the variable is the same whichever we use. The difference is that the post-operator

  • returns the original value before it changes the variable while the pre-operator changes

  • the variable first and then returns the value.

  • Next, there's the comparison operators that compares two values and returns either true or false.

  • Used together with these we have the logical operators. Logical and (&&) evaluates to true if both the left and right sides are true,

  • and logical or (||) is true if either the left or right side is true.

  • To invert a boolean result we also have logical not (!). Note

  • that for both "logical and" and "logical or" the righthand side won't be evaluated if the

  • result is already determined by the left side.

  • Lastly, we have the bitwise operators which allow us to manipulate individual bits inside

  • of an integer. For example, the or operator (|) makes the

  • resulting bit 1 if the bits are set on either side of the operator. These bitwise operators

  • also have shorthand assigment operators.

  • Now, let's look at operator precedence. In C++ expressions are normally evaluated from

  • left to right. However, as can be seen in this table different operators also have different

  • precedents that determine which one gets evaluated first. This same order also applies to many

  • other languages such as Java and C# also. As an example, the logical and operator binds

  • weaker than the relational operators, which in turn binds weaker than the arithmetic operators.

  • To make things clearer we should instead use parenthesis to decide what part of the expression

  • will be evaluated first since parenthesis has the highest precendence of all operators.

The numerical operators in C++ can be grouped into five types: arithmetic, assignment, comparison,

字幕と単語

ワンタップで英和辞典検索 単語をクリックすると、意味が表示されます

B1 中級

C++チュートリアル - 06 - 演算子 (C++ Tutorial - 06 - Operators)

  • 386 42
    Jjli Li に公開 2021 年 01 月 14 日
動画の中の単語