Program to print Factorial of a number in c++ - c++

Question

Q) Write a program that defines and tests a factorial function. The factorial of a number is the product of all whole numbers from 1 to N.
For example, the factorial of 5 is 1 * 2 * 3 * 4 * 5 = 120
Problem: I am able to print the result,but not able to print like this :
let n = 5
Output : 1 * 2 * 3 * 4 * 5 = 120;
My Code:
# include <bits/stdc++.h>
using namespace std;
int Factorial (int N)
{
int i = 0;int fact = 1;
while (i < N && N > 0) // Time Complexity O(N)
{
fact *= ++i;
}
return fact;
}
int main()
{
int n;cin >> n;
cout << Factorial(n) << endl;
return 0;
}

Answer 1

I am able to print the result,but not able to print like this : let n
= 5 Output : 1 * 2 * 3 * 4 * 5 = 120;
That's indeed what your code is doing. You only print the result.
If you want to print every integer from 1 to N before you print the result you need more cout calls or another way to manipulate the output.
This should only be an idea this is far away from being a good example but it should do the job.
int main()
{
int n;cin >> n;
std::cout << "Factorial of " << n << "!\n";
for (int i =1; i<=n; i++)
{
if(i != n)
std::cout << i << " * ";
else
std::cout << n << " = ";
}
cout << Factorial(n) << endl;
return 0;
}
Better approach using std::string and std::stringstream
#include <string>
#include <sstream>
using namespace std;
int main()
{
int n;
cin >> n;
stringstream sStr;
sStr << "Factorial of " << n << " = ";
for (int i = 1; i <= n; i++)
{
if (i != n)
sStr << i << " * ";
else
sStr << i << " = ";
}
sStr << Factorial(n) << endl;
cout << sStr.str();
return 0;
}