Re: Does Casting Slow a Program Down?

PeterOut wrote:
If I had code like this.

unsigned short usLimit=10
int a[10], i;

for (i=0; i<(int)usLimit; ++i)
{
a[i]=(int)usLimit;
}

would it run slower than this?

int a[10], i, iLimit=10;

for (i=0; i<iLimit; ++i)
{
a[i]=iLimit;
}

Quality of code generation is implementation defined. A good optimiser
might be able to figure out that usLimit is not changed and hence, use
a single, cached value. On some hardware, short and int might be of
the same size and representation. In such cases, the cast never takes
up any object code. But speed of execution is not specified by the
standard and no guarantees are made. An assignent statement that takes
ten days to complete is perfectly legal, as per the standard, as long
as all the side effects are resolved before the next sequence point.

.

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