What does —= mean in C language?

In C language, the -= operator is a compound assignment operator, which subtracts a specific value from the value of a variable, which is equivalent to two operations: subtraction and assignment. An example of its use is to subtract 5 from the value of the variable x from 10 to 5. Similar to other compound assignment operators, such as =, *=, etc. The -= operator can improve efficiency and can only be applied to numeric type variables.

The meaning of - in C language

In C language, -= is a compound assignment operator, Used to subtract a specific value from the value of a variable. Its meaning is equivalent to two separate operations: first subtracting the specified value from a variable, and then storing the result back to that variable.

Usage Example

<code class="c">int x = 10;
x -= 5;</code>

In the above example, the value of variable x was originally 10. The -= operator subtracts 5 from the value of x, resulting in 5. The result is then stored back into x, so the final value of x becomes 5.

Comparison with other operators

-= operator is similar to other compound assignment operators, for example:

• =: will Add a specific value to the variable value
• -=: Subtract a specific value from the variable value
• *=: Multiply the variable value by a specific value
• /=: Divide a variable value by a specific value

Efficiency

Using the -= operator is better than using the equivalent separate operation (i.e. More efficient as it reduces lines of code and improves readability.

Note

-= operator can only be used for numeric type variables. If you try to use it with other types, such as string or character, an error will be generated.

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