Fibonacci setup

[bill_marly]

Here is my code for my fibonacci sequence. It is a function, where I call it in the main funtion.
It prints everything on one line, up to the the users max value. How is it possible to ask the user how many fib. numbers they want per line?

int fibonacci(int N)
{
int a,b,c,x;
a=1;
b=1;

for(x=1; x <= N; x++)
{
if (a <= N)
{
cout<< a << endl;
}
c= a+b;
a= b;
b= c;
}
}

[t i l e x]

Code: Select all

int fibonacci(int N)  {
    int a,b,c, nb_fib;
    a=1;
    b=1;
    N -= 1;

    std::cout << "Enter the number of fibonacci numbers before eol character:";
    std::cin >> nb_fib;

    for(int i = 1; i <= N; ++i)  {
        if(a <= N)         std::cout << a << '\t';
        if(!(i % nb_fib))  std::cout <<  std::endl;
    }
    std::cout << b;

    c = a+b;
    a = b;
    b = c;
}

PS: Might want to look at this:

Code: Select all

int nb_fib; // assumed you will give it a value

void Fibonnacci(int a, int b, int N) {
    if(N) {
        std::cout << a;
        if(!(N % nb_fib))
            std::cout << std::endl;
        Fibonnacci(b, a+b, --N);
    }
    std::cout << std::endl << "End of the fibonnacci sequence.";
}

[Guest]

I tried the code.... but it doens't work. All I get is a bunch of ones?
Also, what is the purpose of the 2nd function that you coded? void function?

[Guest]

I'm using bloodshed compiler, in C++

[t i l e x]

Sorry, this is my error on the first function:

Code: Select all

int fibonacci(int N)  {
    int a,b,c, nb_fib;
    a=1;
    b=1;
    N -= 1;

    std::cout << "Enter the number of Fibonacci numbers before eol character:";
    std::cin >> nb_fib;

    for(int i = 1; i <= N; ++i)  {
        if(a <= N)         std::cout << a << '\t';
        if(!(i % nb_fib))  std::cout <<  std::endl;

        c = a+b;
        a = b;
        b = c;
    }
    std::cout << b;
}

This one should work fine.

The other function is a recursive version of the one above. Try this:

Code: Select all

#include <iostream>

int nb_fib; // assumed you will give it a value

void Fibonnacci(int N, int a = 1, int b = 1) {
    if(N) {
        std::cout << a;
        if(!(N % nb_fib))
            std::cout << std::endl;
        Fibonnacci(b, a+b, --N);
    }
    std::cout << std::endl << "End of the fibonnacci sequence.";
}

int main(void) {
    std::cout << "Enter the number of fibonnacci numbers to output on each line: ";
    std::cin >> nb_fib;

    int N;
    std::cout << "Enter the number of fibonnacci numbers to generate: ";
    std::cin >> N;

    Fibonnacci(N);
    return 0;
}

*EDIT* Wow, that is close to being nearly close of looking somewhat like Alvaro code.

[Darryl]

*EDIT* Wow, that is close to being nearly close of looking somewhat like Alvaro code.

Naw, here is Alvaro Fibonacci code.

[Guest]

Here is my code....
int fibonacci1(int N)
{
int a,b,c, nb_fib;
a=1;
b=1;
N -= 1;

cout << "Enter the number of Fibonacci numbers per line: ";
cin >> nb_fib;

for(int i = 1; i <= N; ++i)
{
if(a <= N)
cout << a << '\t';
if(!(i % nb_fib))
cout << endl;

c = a+b;
a = b;
b = c;
}
cout << b;
}



Here is my output.....
Enter the number of Fibonacci numbers per line: 4
1 1 2 3
5 8 13 21
34








-1323752223
-811192543 -1109825406
Press any key to continue . . .




Why am I getting those huge negative numbers at the end??? It does that when I type anything over 34, I think. Have any idea??

[Guest]

Also, in your code, you use '\t'
What exactly is that? I've never seen that before??

[Darobat]

escape sequence for tab.

[.]

Here is my code....

Code: Select all

int  fibonacci1(int N)
{
   int a,b,c, nb_fib;
   a=1;
   b=1;
   N -= 1;

   cout << "Enter the number of Fibonacci numbers per line: ";
   cin >> nb_fib;

   for(int i = 1; i <= N; ++i)
   {
      if(a <= N)
         cout << a << '\t';
      if(!(i % nb_fib))
         cout << endl;

      c = a+b;
      a = b;
      b = c;
   }
   cout << b;
}

Here is my output.....
Enter the number of Fibonacci numbers per line: 4
1 1 2 3
5 8 13 21
34


-1323752223
-811192543 -1109825406
Press any key to continue . . .


Why am I getting those huge negative numbers at the end??? It does that when I type anything over 34, I think. Have any idea??

If I pass the function the value 100 for N.

Code: Select all

for(int i = 1; i <= N; ++i)

with your code

Code: Select all

        if(a <= N)
            cout << a << '\t';

this will fail after 11 iterations and that leaves 89 more iteration in your for loop with no way to break out of the loop.

[Guest]

When I pass it 100, here's what I get.

0
1
1
2
3
5
8
13
21
34
55
89
-1323752223
-811192543
-298632863
-1109825406
-1408458269
-1781832971
-1418756969
-1055680967
-1709589543
-944741150
-1958435240
-1262539787
-188547518
-2015728079
-433386095
-1036647147
-660827267
-285007387
-945834654
-1230842041
-1289228135
-401779575
-1691007710
-2092787285
-1581614984
-1070442683
-2079590721
-1507123775
-798870975
-90618175
-889489150

Press any key to continue . . .



What is going wrong?[/code]

[.]

You are over running the range of an int. I think that you will agree that

Code: Select all

-1323752223
-811192543

These values are less than 100?
But the root of this problems is in you for statement.

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for(int i = 1; i <= N; ++i)

You have not given the loop a way to stop if

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if(a <= N)

This will be after 12 iterations and you go on for another 88 which exceed the range of an int. You could try "unsigned int" but that is probably a band aid approach. The real solution would be to break out of the loop when

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if(a <= N)

so you could try this

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   for(int i = 1; i <= N && a <= N; ++i)
   {
      if(a <= N)

[.]

also if this is you complete function there is a little problem

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int  fibonacci1(int N)
{
   int a,b,c, nb_fib;
   a=1;
   b=1;
   N -= 1;

   cout << "Enter the number of Fibonacci numbers per line: ";
   cin >> nb_fib;

   for(int i = 1; i <= N; ++i)
   {
      if(a <= N)
         cout << a << '\t';
      if(!(i % nb_fib))
         cout << endl;

      c = a+b;
      a = b;
      b = c;
   }
   cout << b;
}

You give this function a return type of int and there is no return statement ( this should be a compiler error for you ) so you should give it a return statement or make it void

Code: Select all

void  fibonacci1(int N)

[not the OP]

Sorry, this is my error on the first function:

Code: Select all

int fibonacci(int N)  {
    int a,b,c, nb_fib;
    a=1;
    b=1;
    N -= 1;

    std::cout << "Enter the number of Fibonacci numbers before eol character:";
    std::cin >> nb_fib;

    for(int i = 1; i <= N; ++i)  {
        if(a <= N)         std::cout << a << '\t';
        if(!(i % nb_fib))  std::cout <<  std::endl;

        c = a+b;
        a = b;
        b = c;
    }
    std::cout << b;
}

This one should work fine.

The other function is a recursive version of the one above. Try this:

Code: Select all

#include <iostream>

int nb_fib; // assumed you will give it a value

void Fibonnacci(int N, int a = 1, int b = 1) {
    if(N) {
        std::cout << a;
        if(!(N % nb_fib))
            std::cout << std::endl;
        Fibonnacci(b, a+b, --N);
    }
    std::cout << std::endl << "End of the fibonnacci sequence.";
}

int main(void) {
    std::cout << "Enter the number of fibonnacci numbers to output on each line: ";
    std::cin >> nb_fib;

    int N;
    std::cout << "Enter the number of fibonnacci numbers to generate: ";
    std::cin >> N;

    Fibonnacci(N);
    return 0;
}

*EDIT* Wow, that is close to being nearly close of looking somewhat like Alvaro code.

you do realize that nether of the two work?
The first one does not break out of the loop before overflows the int and and the second one does not print all the values to the screen?

[Guest]

Finally... I got it to work....

Thank You guys!!!!!