subs

Subtract two signed integers, checking for overflow.

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

int subs(int x, int y, bool overflow)
long subs(long x, long y, bool overflow)
cent subs(cent x, cent y, bool overflow)
nothrow @safe @nogc pure pragma(inline, true)
static if(is(cent))
cent
subs
()
(
cent x
,
cent y
,
ref bool overflow
)

Parameters

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

Return Value

Type: cent

the difference

Examples

bool overflow;
assert(subs(2, -3, overflow) == 5);
assert(!overflow);

assert(subs(1, -int.max + 1, overflow) == int.max);
assert(!overflow);

assert(subs(int.min + 1, 1, overflow) == int.min);
assert(!overflow);

assert(subs(int.max, -1, overflow) == int.min);
assert(overflow);

overflow = false;
assert(subs(int.min, 1, overflow) == int.max);
assert(overflow);

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

bool overflow;
assert(subs(2L, -3L, overflow) == 5);
assert(!overflow);

assert(subs(1L, -long.max + 1, overflow) == long.max);
assert(!overflow);

assert(subs(long.min + 1, 1, overflow) == long.min);
assert(!overflow);

assert(subs(-1L, long.min, overflow) == long.max);
assert(!overflow);

assert(subs(long.max, -1, overflow) == long.min);
assert(overflow);

overflow = false;
assert(subs(long.min, 1, overflow) == long.max);
assert(overflow);

assert(subs(0L, 0L, overflow) == 0);
assert(overflow);                   // sticky

subs

Parameters

Return Value

Examples

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