Hi yea I'm just beginning ot work with C and I had a two questions. By the way thanks to everyone who has helped me in the past, I much obliged.

Ok here goes:
1) I'm trying calculate the distance between two points on a plain and i was trying to use the sqrt() function from math.h, but I can't get the syntax right. I was trying to do this basically:

/* brace yourself for some bad pseudo code */
x, y are my variables for the squared value of the the previous computation which is (x2- x1)e2 + (y2 - y1)e2 so far i've squared subtracted the coordinances and squared them so to complete the distance formula:

distance = sqrt(x + y)

When I man'd sqrt it showed the syntax as double (sqrt double x) I think? I tried that and every other substitution with double and such and still can't get it working. I've also just tried distance = sqrt(x +y) and that didn't work either.

Any ideas?

2) How would I go about in an if declaration I wanted a to exectute the effect if a number was between two numbers. e.g.:

if (x < 70 > 60)
printf("Student has D')

I'm not sure how do setup the statement would the && operator work? or would what I just typed above work? Sorry I'm lost any help would be great.

Thanks everyone,
Spiros

1) i am not very sure abt this, but here it goes,

if x and y are integer, distance is double, then

distance = sqrt(x+y) shd work. If not , try distance = (double) sqrt(x+y);

if distance is integer,

distance = (int) sqrt(x+y);

one of the above will work....i think the problem is: output is double where as your variabl might be integer, so u need typecasting.

2) try :
if ((x>70) && (x <80)) {
...
}

this will do the trick....

PS: please read some elimentary C tutorial.

Regards,
Rajat Garg
Student, Stanford University

In other words, Rajat and I are guessing that the problem is numeric conversion errors between floats, doubles and integers.

Floating point constants (like "1.0") default to "float" in C/C++ (thankfully, they now default to "double" in languages like Java and C#), input parameters and return values are usually "double" in the C/C++ math libraries, and it sounds like at least some of your variables are "int".

The easiest, safest approach is:
1. Make all of the variables you pass into the math routines, and use in arithmetic expressions, "double".

2. Explicitly cast *ALL* of your floating point literals to "double", *ALWAYS*:
x = y * (double)1.0;

Good luck .. PSM