What does the operator '!=' check for in programming?

The operator '!=' is used in programming to check for "not equal" values. When this operator is applied between two operands, it evaluates to true if the values on either side of the operator are not equal to each other. This allows programmers to create conditional statements that execute specific code when two values do not match, which is essential for decision-making in algorithms and conditional processes.

For instance, if you have two variables, a and b, the expression a != b will return true if a and b hold different values. This is commonly utilized in loop constructs, conditional statements, and various logical comparisons to ensure that certain actions occur only when values differ.

Understanding this operator is crucial for effectively controlling flow in programming, as it helps in filtering data, making decisions, and managing program logic based on value comparisons.