Exercise: average without overflow

Write a function int average(int a, int b) that returns the arithmetic mean of the two numbers. Drop the fraction, as / does with two int operands: 7.5 becomes 7, and -7.5 becomes -7.

• average(10, 20) → 15
• average(-7, -8) → -7
• average(INT_MAX, INT_MAX) → INT_MAX

Constraints: a and b are any int values from INT_MIN to INT_MAX, so a + b may not fit in an int.

Do not add extra #include lines unless the task says so explicitly.