CODEWITHSUNDEEP
cfactorial
Woong-Sup Jung
Woong-Sup Jung

Reputation: 2337

C Programming factorial outputting wrong values

int main (void)
{
   int i;
   for (i=1; i<=20; i++) {
       int j;
       unsigned long long fac = 1;

       for ( j = 1; j<=i; ++j) {
          fac *= j;
       }

       printf ("%2i! = %ld\n", i, fac);
    }

return 0;
}

From 14! to 20! outputs wrong values.

It either gives a negative number or the number is not big enough.. what is the problem?

Upvotes: 2

Views: 647

Answers (3)

Sagar Jauhari
Sagar Jauhari

Reputation: 588

You are calculating correctly but printing incorrectly! use %llu : 

  printf ("%2i! = %llu\n", i, fac);

  20! = 2432902008176640000

There!

Upvotes: 2

makes
makes

Reputation: 6548

The variable fac is of type unsigned long long. The correct format specifier for this type is is %llu:

printf ("%2i! = %llu\n", i, fac);

Upvotes: 2

Shamim Hafiz - MSFT
Shamim Hafiz - MSFT

Reputation: 22114

printf ("%2i! = %ld\n", i, fac);

The problem is here, use proper notation for unsigned long long type value

Try:

printf ("%2i! = %llu\n", i, fac);

Upvotes: 8

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