Don't overflow

Reason

Overflow usually makes your numeric algorithm meaningless. Incrementing a value beyond a maximum value can lead to memory corruption and undefined behavior.

Example, bad

int a[10];
a[10] = 7;   // bad, array bounds overflow

for (int n = 0; n <= 10; ++n)
    a[n] = 9;   // bad, array bounds overflow

Example, bad

int n = numeric_limits<int>::max();
int m = n + 1;   // bad, numeric overflow

Example, bad

int area(int h, int w) { return h * w; }

auto a = area(10'000'000, 100'000'000);   // bad, numeric overflow

Exception

Use unsigned types if you really want modular arithmetic.

Alternative: For critical applications that can afford some overhead, use a range-checked integer and/or floating-point type.

Enforcement

???