What do ++ and -- mean in java?

In Java, and -- represent the increment and decrement operators, used to modify the value of a variable: The increment operator ( ): has prefix and suffix forms, and increments the variable value by 1. Decrement operator (--): Available in prefix and suffix forms, decrements the variable value by 1. There are a wide range of application scenarios, including loop counting, data structure update, Boolean value inversion and one-time value increment or decrement.

The meaning of and-- in Java

In Java, and-- are self-increasing and self-decreasing operator. They are usually used to modify the value of a variable.

Auto-increment operator ( )

Auto-increment operator is used to increment the value of a variable by 1. There are two forms of increment operators:

• Prefix increment : Place before the expression. For example:

  <code class="java">int count = 5;
  ++count; // 将 count 的值增加 1，现在 count 等于 6</code>

• Postfix increment: Place after the expression. For example:

  <code class="java">int count = 5;
  count++; // 等同于前缀自增，将 count 的值增加 1，现在 count 等于 6</code>

Decrement operator (--)

Decrement operator -- is used to decrement the value of a variable by 1. Similar to the increment operator, there are two forms of decrement operators:

• Prefix decrement (prefix decrement): Place -- before the expression . For example:

  <code class="java">int count = 5;
  --count; // 将 count 的值减少 1，现在 count 等于 4</code>

• Postfix decrement: Place -- after the expression. For example:

  <code class="java">int count = 5;
  count--; // 等同于前缀自减，将 count 的值减少 1，现在 count 等于 4</code>

Application scenarios

Increment and decrement operators are widely used in various scenarios, such as:

• Loop counting
• Update of pointers in the data structure
• Inversion of Boolean value
• Increment or decrement of one-time value (for example, used for log ID or transaction ID)

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