[unix-history] / usr / lib / learn / C / L32.1a

#print
Write a program
   pair(a,b)
which accepts as arguments two pointers to integers
and swaps the integers if necessary so that the
first argument points to the larger one; that is
	int x,y;
	x = 9;
	y = 15;
	pair( &x, &y);
results in x being 15 and y 9.  Leave the program
on file "pair.c"; compile, test it, and type "ready".
#once #create tzaqc.c
main()
{
	int x,y;

	y=200;
	x = 0;
	pair(&y, &x);
	if (x != 0 || y != 200) 
		return(1);
	pair(&x,&y);
	if (x != 200 || y != 0) 
		return(1);
	x = 30;
	y = 23097;
	pair(&x,&y);
	if (x != 23097 || y !=  30) 
		return(1);
	return(0);
}
#user
cc tzaqc.c pair.o
a.out 
#succeed
pair(a, b)
int *a, *b;
{
	int t;

	if (*a <= *b) {
		t = *a;
		*a = *b;
		*b = t;
	}
}
#log
#next
33.1a 10
Commit	Line	Data
d6c1f319 C	1	#print
	2	Write a program
	3	pair(a,b)
	4	which accepts as arguments two pointers to integers
	5	and swaps the integers if necessary so that the
	6	first argument points to the larger one; that is
	7	int x,y;
	8	x = 9;
	9	y = 15;
	10	pair( &x, &y);
	11	results in x being 15 and y 9. Leave the program
	12	on file "pair.c"; compile, test it, and type "ready".
	13	#once #create tzaqc.c
	14	main()
	15	{
	16	int x,y;
	17
	18	y=200;
	19	x = 0;
	20	pair(&y, &x);
	21	if (x != 0 \|\| y != 200)
	22	return(1);
	23	pair(&x,&y);
	24	if (x != 200 \|\| y != 0)
	25	return(1);
	26	x = 30;
	27	y = 23097;
	28	pair(&x,&y);
	29	if (x != 23097 \|\| y != 30)
	30	return(1);
	31	return(0);
	32	}
	33	#user
	34	cc tzaqc.c pair.o
	35	a.out
	36	#succeed
	37	pair(a, b)
	38	int a, b;
	39	{
	40	int t;
	41
	42	if (a <= b) {
	43	t = *a;
	44	a = b;
	45	*b = t;
	46	}
	47	}
	48	#log
	49	#next
	50	33.1a 10