subu

Subtract two unsigned integers, checking for overflow (aka borrow).

The overflow is sticky, meaning a sequence of operations can be done and overflow need only be checked at the end.

uint subu(uint x, uint y, bool overflow)
ulong subu(ulong x, ulong y, bool overflow)
ucent subu(ucent x, ucent y, bool overflow)
nothrow @safe @nogc pure pragma(inline, true)
static if(is(ucent))
ucent
subu
()
(
ucent x
,
ucent y
,
ref bool overflow
)

Parameters

x ucent: left operand
y ucent: right operand
overflow bool: set if an overflow occurs, is not affected otherwise

Return Value

Type: ucent

the difference

Examples

bool overflow;
assert(subu(3, 2, overflow) == 1);
assert(!overflow);

assert(subu(uint.max, 1, overflow) == uint.max - 1);
assert(!overflow);

assert(subu(1, 1, overflow) == uint.min);
assert(!overflow);

assert(subu(0, 1, overflow) == uint.max);
assert(overflow);

overflow = false;
assert(subu(uint.max - 1, uint.max, overflow) == uint.max);
assert(overflow);

assert(subu(0, 0, overflow) == 0);
assert(overflow);                   // sticky

bool overflow;
assert(subu(3UL, 2UL, overflow) == 1);
assert(!overflow);

assert(subu(ulong.max, 1, overflow) == ulong.max - 1);
assert(!overflow);

assert(subu(1UL, 1UL, overflow) == ulong.min);
assert(!overflow);

assert(subu(0UL, 1UL, overflow) == ulong.max);
assert(overflow);

overflow = false;
assert(subu(ulong.max - 1, ulong.max, overflow) == ulong.max);
assert(overflow);

assert(subu(0UL, 0UL, overflow) == 0);
assert(overflow);                   // sticky

subu

Parameters

Return Value

Examples

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