Objective

Implement student_stats, which reduces an array of student records into one stats struct holding the lowest score, the highest score, the integer mean, and the name of the top scorer.

Steps

• student holds a const char *name and an int score. stats holds int min, int max, int mean, then const char *best. The starter ships both definitions and Grademe compiles its tests against exactly those, so leave the fields and their order alone.
• a points to n records. Read exactly n, never one more, and write only through out. The array itself is const, so nothing in it moves or changes.
• out->min gets the lowest score, out->max the highest, and out->best the name of the student holding that highest score.
• Two students tied on the top score: best is the first of them in array order. A later record with an equal score never takes over.
• out->mean is an int, so the mean is truncated toward zero rather than rounded. A total of 21 over two students gives 10. A total of -9 over two students gives -4, not -5.
• Accumulate the total in a long. Ten students at 300000000 add up to 3000000000, which an int cannot hold, and the mean read back out of an overflowed accumulator is worthless.
• When n is 0, write 0 into min, max and mean, and NULL into best. Leaving out untouched is not the same thing: the tests fill it with junk first and check that you overwrote all four fields.
• Scores use the full int range, INT_MIN and INT_MAX included. Seeding min and max from a[0] sidesteps that problem; seeding them from 0 does not.
• The tests print one line per call, shaped min=<min> max=<max> mean=<mean> best=<best>, with best shown as null when the pointer is NULL.

Objective

Implement student_stats, which reduces an array of student records into one stats struct holding the lowest score, the highest score, the integer mean, and the name of the top scorer.

Steps

• student holds a const char *name and an int score. stats holds int min, int max, int mean, then const char *best. The starter ships both definitions and Grademe compiles its tests against exactly those, so leave the fields and their order alone.
• a points to n records. Read exactly n, never one more, and write only through out. The array itself is const, so nothing in it moves or changes.
• out->min gets the lowest score, out->max the highest, and out->best the name of the student holding that highest score.
• Two students tied on the top score: best is the first of them in array order. A later record with an equal score never takes over.
• out->mean is an int, so the mean is truncated toward zero rather than rounded. A total of 21 over two students gives 10. A total of -9 over two students gives -4, not -5.
• Accumulate the total in a long. Ten students at 300000000 add up to 3000000000, which an int cannot hold, and the mean read back out of an overflowed accumulator is worthless.
• When n is 0, write 0 into min, max and mean, and NULL into best. Leaving out untouched is not the same thing: the tests fill it with junk first and check that you overwrote all four fields.
• Scores use the full int range, INT_MIN and INT_MAX included. Seeding min and max from a[0] sidesteps that problem; seeding them from 0 does not.
• The tests print one line per call, shaped min=<min> max=<max> mean=<mean> best=<best>, with best shown as null when the pointer is NULL.