What does a=-a mean in C language?

In C language, "a=-a" sets "a" to 0: the unary operator "-" takes the inverse of the expression and changes "a" to "-a". Assign "-a" to "a", changing the value of "a" to 0.

The meaning of a=-a in C language

In C language, a=-a is a Equivalent to the operation of a=0.

Detailed description

• The function of the unary operator - is to take the opposite number of the expression.
• In the operation of a=-a, first take the inverse of a to get -a.
• Then assign -a to a, which is equivalent to changing the value of a to 0.

Example

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

// 将 a 设为 0
a = -a;

// 现在 a 的值为 0</code>

It should be noted that:

• If the value of a is a floating point number , then a=-a may cause rounding errors, causing the value of a to not be exactly 0.
• a=-a operation can be used to reset any non-zero value to 0, regardless of its type or sign.

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