C++ code-- Factorial Recursion

Write code to complete PrintFactorial()'s recursive case. Sample output if userVal is 5:

5! = 5 4 3 2 1 = 120

#include

using namespace std;

void PrintFactorial(int factCounter, int factValue){

int nextCounter = 0;

int nextValue = 0;

if (factCounter == 0) { // Base case: 0! = 1

cout << "1" << endl;

}

else if (factCounter == 1) { // Base case: Print 1 and result

cout << factCounter << " = " << factValue << endl;

}

else { // Recursive case

cout << factCounter << " ";

nextCounter = factCounter - 1;

nextValue = nextCounter factValue;

}

}

int main() {

int userVal = 0;

userVal = 5;

cout << userVal << "! = ";

PrintFactorial(userVal, userVal);

return 0;

}

Handle the print outside of the factorial function, which only needs one userVal when called.

int factorial( int foo )
{
if( foo == 1 )
return 1;
else
return( foo * factorial( foo - 1 ) );
}

Answer Link

joaobezerra joaobezerra · Answer 2 · 2019-12-26T10:52:47-05:00

Answer:

void PrintFactorial(int factCounter, int factValue){

int nextCounter = 0;

int nextValue = 0;

if (factCounter == 0) { // Base case: 0! = 1

cout << "1" << endl;

}

else if (factCounter == 1) { // Base case: Print 1 and result

cout << factCounter << " = " << factValue << endl;

}

else { // Recursive case

cout << factCounter << " ";

nextCounter = factCounter - 1;

nextValue = nextCounter factValue;

printFactorial(nextCounter, nextValue);

}

Explanation:

The only things that is left is calling the recursive function in the else statement. It is the bolded command on the answer.

factCounter is the value we are multiplying. In the function, it is nextCounter. So for 5, it is 5, then 4, then 3, until 0...

factValue is the value of the factorial. In the function, it is nextValue So it is 5, then 54 = 20, then 543 = 60, then...

void PrintFactorial(int factCounter, int factValue){

int nextCounter = 0;

int nextValue = 0;

if (factCounter == 0) { // Base case: 0! = 1

cout << "1" << endl;

}

else if (factCounter == 1) { // Base case: Print 1 and result

cout << factCounter << " = " << factValue << endl;

}

else { // Recursive case

cout << factCounter << " ";

nextCounter = factCounter - 1;

nextValue = nextCounter * factValue;

printFactorial(nextCounter, nextValue);

}