1. Help with a program

My prof. wantedme to write a C program that calculates the sine of x with a truncation error less than .000001. He also says that for each iteration of the series I should print out the iteration number, the calculated value, truncation error, and the C math librar calculated sine or x. I'm not sure whether I need the printf and the scanf that prompts the user to input a number, or what I should set myint equal to. If you can help in any way, I would greatly appreciate it. Thank you,
Kristina

#include <stdio.h>
#include <math.h>
main()
{
double iter, flipflop, num, fact, k, sinx, mynum;
num=1;
iter=1;
fact=1;
for(k=2; k<=iter; k++);
{
fact=fact*k;
}
do
{
pow(num,iter);
sinx=sinx + num/fact*flipflop;
printf("truncation error %f\n",sinx);
sin(num);
~~>scanf("%d " , mynum);
printf("iteration number %f\n", iter);
printf("math library calculation %f\n",sin(num));
printf("the calculated value is %f\n",sinx);
iter=iter+2;
flipflop=-1;
}
while(num/fact <= .000001);
}

2. You and everyone else... Judging by the time difference between your post and this other one, I'd say your homework's about due now, huh?

3. Well you've got most of the bits for the airplane, but it's no where near able to fly yet.

Some things
1. for(k=2; k<=iter; k++);
See that ; at the end?
This loop does exactly nothing, and since iter is 1 when it enters the loop, it does nothing zero times

2. {
> fact=fact*k;
> }
This isn't being controlled by the previous loop, so it happens just once. It wouldn't have happened at all, if you'd not put the trailing ; on the for loop.

3. unassigned results
> pow(num,iter);
> sin(num);

4. flipflop=-1;
So it starts off uninitialised, then it gets stuck at -1
I think you meant to
a) initialise it to 1
b) say flipflop = -flipflop;

4. Thanks Salem, but what do you suppose iter should be equal to??

5. A number you increment until
"with a truncation error less than .000001"