What is the difference between `==` and `=` in C?

In the C programming language, the distinction between == and = is fundamental to understanding how variables are manipulated and how comparisons are made within the code. The operator == is used for checking equality between two values. This means when you use ==, you are determining whether the values on both sides of the operator are the same. For example, in the expression a == b, the outcome is a boolean value indicating whether the value of a is equal to the value of b.

On the other hand, = is known as the assignment operator. It is used to assign a value to a variable. For instance, when you write x = 5, you are not comparing x to 5; rather, you are assigning the value 5 to the variable x. The distinction is crucial when writing conditions, as using = where == is intended would lead to unintended assignments rather than comparisons, often resulting in logical errors.

Understanding this difference helps prevent common mistakes in programming when control flow is dependent on the outcome of comparisons.