calculating a function

here is the code quzah starte for me and I added the cout and cin but I'm unsure where to add the PowerInt(n) =(n!)/n^2 formula. I think I should be adding that somewhere because it states how to test the variable that is entered or am I completly wrong?

Code:

---

#include <iostream>
#include <stdlib.h>

using namespace std;

int main()

float p(int i)

{
    if( i < 10 && i > 1 )
    {
        int x = i*i;
            y;
        float z

        cout << "enter a number" << endl;
cin >> z;

        return z / (float)x;
    }
    return 1.0;
}

---

Code:

---

#include <iostream>
#include <stdlib.h>

using namespace std;

int main();  //Took an error out when I added semicolon

float p(int i)

{
    if( i < 10 && i > 1 )
    {
        int x = i*i;
        int y;    ///Needed variable int
        float z;    ///Forgot semicolon

        cout << "enter a number" << endl;
cin >> z;

        return z / (float)x;
    }
    return 1.0;
}

---

That fixed it when I compiled. I got these 2 errors when I tried to build however.

Code:

---

Compiling...
Cpp1.cpp
c:\compiled\float\cpp1.cpp(14) : warning C4101: 'y' : unreferenced local variable
Linking...
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/Cpp1.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

Cpp1.exe - 2 error(s), 1 warning(s)

---

I might be wrong just trying to help though :D

Ug. No that's not what I started. Well actually, it's part of what I started, used incorrectly. 'p' is a function. It is not a part of main. Before 'y', that was a , not a ;

Furthermore, the answer was given in your original thread. You ignored the second point of my illustration. Just read the original thread and pay attention to the provided code.

Quzah.

well I added a few things, sorry about that. I guess this program is just really hard. I'm going to look in the text book again and see if I cant put your examples and their examples together and figure somethign out.

Bryan

this again, i thought this was resolved.

I made up a new code, and it seems to work for the most part until it tries to calculate the PowerInt. I know where my problem is but I cant seem to make the n! do what it should. It needs to multiply. If user enters a 4 then it needs to multiply 1*2*3*4/4^2 but I cant seem to make it do that. Any more suggestions.

Thanks

Code:

---

#include <iostream>

using namespace std;

int main()

{
        int iNum;                //stores input value
        int iSum;                //stores sum

        cout << "Please enter an interger: "; //user enters number
        cin >> iNum;        //letter stored
       

        while (iNum >= 1 && iNum <= 10)
        {
                iSum = iNum!/iNum*iNum; //THIS IS MY PROBLEM
                       
                cout << "PowerInt" <<"(" << iNum << ") =" <<iSum << endl;
               
                cout << "Please enter an interger: ";
                cin >> iNum;
               


        }

        cout << "Exiting the program." << endl;
        return 0;
}

---

>> iSum = iNum!/iNum*iNum; //THIS IS MY PROBLEM
Yes it is. First, use some parentheses. Second... ! does not do a factorial in C++ - it's a logical negation. You're going to have to code a factorial function...

Code:

---

int factorial(int number)
{
  int result=1;
  for(int t=number;t=1;t--)
      result*=t;
  return result;
}

---

Use it like this

iSum=factorial(iNum)/(iNum*iNum);

so if I use the code for factorial, which is what i was looking for, I would replace my erro with iSum=fac. ect. But where can I enter the code that you wrote in my program to make it work?

Code:

---

#include <iostream>
#include <iomanip>

using namespace std;

int main()

{
        int iNum;                //stores input value
        int iSum;                //stores sum
       
        cout << "Please enter an interger: "; //user enters number
        cin >> iNum;                                                ; //letter stored
       
       


        while (iNum >= 1 && iNum <= 10)
        {
                iSum=factorial(iNum)/(iNum*iNum); //where do I input that code you wrote to make this not undefined?
               
                cout << "PowerInt" <<"(" << iNum << ") ="  <<iSum << endl;
               
                cout << "Please enter an interger: ";
                cin >> iNum;
               


        }

        cout << "Exiting the program." << endl;
        return 0;
}

---

>> //where do I input that code you wrote to make this not undefined?

somewhere before main()

or stick the line
int factorial(int number);
before int main() and then stick the function that I wrote at the end of your program.

I figured out what the n factroail should look like with your help and researching the book more, but it still dont work out. I get this error when trying to build it. error C2601: 'factorial' : local function definitions are illegal

Code:

---

#include <iostream>

using namespace std;

int main()

{
        int iNum;                //stores input value
        int iSum;                //stores sum
       
        int factorial (int iNum)
        {                              //ITS POINTING TO THIS BRACKET
                int result;

        result = 1;
        while (iNum > 0)
        {
                result = result * iNum;
                iNum--;
        }
        return result;
        }
       
        while (iNum >= 1 && iNum <= 10)
        {
                iSum=factorial(iNum)/(iNum*iNum);

                cout << "Please enter an interger: "; //user enters number
                cin >> iNum;                                                ; //letter stored
                cout << "PowerInt" <<"(" << iNum << ") ="  <<iSum << endl;

               
                cout << "Please enter an interger: ";
                cin >> iNum;
               


        }

        cout << "Exiting the program." << endl;
        return 0;
}

---

Change your code to look like this

Code:

---

#include <iostream>

using namespace std;

int factorial(int iNum);

int main()

{
        int iNum;                //stores input value
        int iSum;                //stores sum
       
        while (iNum >= 1 && iNum <= 10)
        {
                iSum=factorial(iNum)/(iNum*iNum);

                cout << "Please enter an interger: "; //user enters number
                cin >> iNum;                                                ; //letter stored
                cout << "PowerInt" <<"(" << iNum << ") ="  <<iSum << endl;
               
                cout << "Please enter an interger: ";
                cin >> iNum;
        }

        cout << "Exiting the program." << endl;
        return 0;
}

int factorial (int iNum)
{                           
        int result;

        result = 1;
        while (iNum > 0)
        {
                result = result * iNum;
                iNum--;
        }
        return result;
}

---

blackrat did you even run your program? It goes right to the exiting the program string.

Code:

---

int iNum;                //stores input value
        int iSum;                //stores sum
       
        while (iNum >= 1 && iNum <= 10)

---

so what does iSum and iNum == there??

Code:

---

int factorial (int iNum)
{                           
        int result;

        result = 1;
        while (iNum > 0)
        {
                result = result * iNum;
                iNum--;
        }
        return result;
}

---

will always return 0

thanks for everyone who helped me with this. I appreciate it so much. After a few days of this I finally got it. I could not get them to print out in decimals becuase I was putting int iNum and int iSum and they needed to be float iNum and float iSum...it works great now. thanks again

Code:

---

//**************************
//This program calculates
//an n! factorial
//**************************

#include <iostream>

using namespace std;

int factorial(int iNum);                //number whose factorial is to be computed

int main()

{

        float iNum;                //stores input value
        float iSum;                //stores sum
       

        do
        {
                cout << "Please enter an interger: "; //user enters number
                cin >> iNum;                                                ; //letter stored
                if (iNum<=-1)break;                        //if negative number program will end
                iSum=factorial(iNum)/(iNum*iNum); //call to factorial
                cout << "PowerInt" <<"(" << iNum << ") ="<<iSum << endl; //output

        }while(true);                //if true program will exit
        cout << "Exiting the program." << endl;        //end program
       
        return 0;
}

int factorial (int iNum)                                //n! factorial
{                           
        int result;

        result = 1;
        while (iNum > 1)
        {
                result = result * iNum;
                iNum--;
        }
        return result;
}

---