What does == mean in C language?

In C language, "==" is the equality operator, which is used to compare whether the values ​​of two expressions are equal. It returns 1 (true) for equality and 0 (false) for inequality. Unlike the assignment operator "=", which is used to compare values, "=" is used to assign a value to a variable.

The meaning of "==" in C language

In C language, "==" isEquality operator is used to compare whether the values ​​​​of two expressions are equal.

Usage:

<code class="c">if (a == b) {
  // 如果 a 等于 b，执行此代码块
}</code>

Return value type:

• If the expressions are equal, return 1 (true )
• If the expressions are not equal, 0 (false) is returned

The difference between "=":

• “==” is used to compare the values ​​of two expressions, while “=" is used to assign a value to a variable.

Example:

<code class="c">int a = 5;
int b = 5;

if (a == b) {
  printf("a 和 b 相等\n");
}</code>

Note:

• For basic data types (such as int, float ), you can use "==" to compare values.
• For complex data types such as structures or classes, you can use "==" to compare addresses (pointers) instead of values.
• The priority of "==" is lower than the assignment operator "=", so pay attention to the priority order in expressions.

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