While loop question!

Code:

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#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
float fact;

/* what number do we want to calculate the factorial of? */
num = 10;

/* Initialise the factorial */
fact = 1.0;

/* Count from 2 to num, multiply fact by counter each time */
i = 2;
while ( i <= num) {
  fact = fact *  i;
i = i + 1;
}

/* Print the result */
printf (“The factorial of &#37;d is %f\n”, num, fact);
}

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The point of that was to calculate the factorial of 10, using a while loop, which worked fine, but I have this question that says Alter the program so that the counter counts from num down to 1, rather than the other way .

I tried altering the code in the following way but it didn’t work:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
float fact;

/* what number do we want to calculate the factorial of? */
num = 10;

/* Initialise the factorial */
fact = 1.0;

/* Count from 10 to num, multiply fact by counter each time */
i = 10;
while ( 0< i <= num) {
  fact = fact *  i;
i = i - 1;
}

/* Print the result */
printf (“The factorial of %d is %f\n”, num, fact);
}

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Which should give me the same answer as the first code written but it doesn’t. Where have I gone wrong?

Thanks!

Code:

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while ( 0< I <= num)

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This doesn't do what you think it does.

Code:

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int main() {

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Code:

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return 0;

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i is not declared.

Is this the actual code that you compiled? If it is, what compiler are you using, and what is your warning level set to?

You can use this for while

Code:

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While(0<l && l<=num)

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but in your program l is undeclared . . . Check it out

What do you mean i is not declared...?

I used emacs as the editor.. and i've edited the code slightly maybe it was that..what you mean?

It means you're not telling the compiler what i is. The same goes for num. The compiler can't just guess "oh, i is an int, num is also an int" you have to declare to the compiler that they are.

In code :

Code:

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int i;
int num;

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> While(0<l && l<=num)

Capital i, or any case of L are terrible names for variables. It's also while() not While() ;)

0 < I <= num, is the same as, i E(0,num], in other words

Code:

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if(i > 0 && i <= num)
    /* in range */

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