In the C++ Standard Library header <algorithm>, which of the following is the name of a valid algorithm function that compares two ranges and finds the first position where they differ?

Introduction / Context:
The C plus plus Standard Library provides a powerful header named algorithm that contains many generic functions for operating on ranges of elements. These functions perform tasks such as searching, sorting, comparing, and transforming sequences. Knowing the exact names and purposes of these algorithms is important for effective use of the library. This question asks you to identify a real algorithm function that checks two ranges and finds the first position where they differ.

Given Data / Assumptions:

• We are using standard C plus plus and the header <algorithm>.
• We are interested in functions that work on ranges of iterators.
• One of the options is actually defined by the standard and compares two ranges to detect the first differing element.
• The other options are either misnamed, belong to other headers, or do not exist at all.

Concept / Approach:
The algorithm header defines a function template mismatch that takes two ranges and returns a pair of iterators pointing to the first position where the elements are not equal. The standard also defines functions named min, max, and minmax, but not minimum or maximum as function names. Some names that sound reasonable, such as average or accumulate_all, are not real algorithm functions in the standard library. Therefore, the correct approach is to recall the exact function names defined in <algorithm> and choose the one that is actually present and that matches the described behavior.

Step-by-Step Solution:
Step 1 Recall the common algorithms defined in <algorithm>, such as sort, find, equal, mismatch, min, max, and others. Step 2 Identify which algorithm is specifically used to compare two ranges and report the first position where they differ. This is the role of mismatch. Step 3 Check each option carefully. The names maximum and minimum are not standard C plus plus algorithm function names, even though there are max and min. Step 4 Recognize that average and accumulate_all are not standard algorithm names either. Therefore, mismatch is the only valid algorithm name from <algorithm> among the options.

Verification / Alternative check:
You can verify this by checking typical C plus plus references or by using code completion in a modern integrated development environment. Typing std:: and browsing the functions after including <algorithm> will show mismatch but will not show maximum, minimum, average, or accumulate_all as algorithms. Additionally, reading example code for comparing two arrays often uses std::mismatch to locate the first difference, which confirms its purpose.

Why Other Options Are Wrong:
The option maximum is incorrect because the standard naming is max, not maximum, and max returns the larger of two elements rather than comparing ranges. Similarly, minimum does not exist as a function name; the actual function is min. The option average does not correspond to a standard algorithm; although std::accumulate can be used to compute an average, there is no function literally named average. The option accumulate_all is invented and does not appear in the C plus plus Standard Library. Hence, all of these options are invalid in this context.

Common Pitfalls:
A common pitfall is to rely on intuitive English words rather than the official names used by the standard. Learners often guess maximum or minimum because they sound reasonable, but the library uses shorter names like max and min. Another mistake is to assume that if a feature could be useful, it must exist as a single algorithm, which is not always true. Careful reading of documentation and practicing with real code help avoid these naming errors.

Final Answer:
The valid C plus plus Standard Library algorithm that compares two ranges and finds the first mismatch is mismatch.