# Print Fibonacci series in C++

In this page we will Print Fibonacci series in C++ but before starting program what is Fibonacci series ?

In Fibonacci series, the first number and the second number are total, is the third number.

``first number + second number = third number``

such as, Here is the program,

``````#include<iostream>
using namespace std;

int main()
{
int first=0,second=1,next;
int num;
clrscr();

cout<<"Enter the number of terms in series:";
cin>>num;

cout<<first<<"\t"<<second;

int i=3;
while(i<=num)
{
next=first+second;
cout<<"\t"<<next;
first=second; // now first number is second
second=next; // and second number is next
i++;
}
return 0;
}``````

OUTPUT

``````Enter the number of terms in series: 8
0       1       1       2       3       5``````

Explanation

In the program, we have declared the following variables.

``int num, first,second,next;``

In which variable first and wearable seconds have been initialized and variable numbers have been used to store user input.

Suppose user input is 8

``num =8;``

First of all we have printed the value of variable first and variable second.

After this the loop starts.

We have assigned the value 3 to the variable i here because we have already printed in two terms(variable first and second) of the series.

if your are interested then here is the complete process To Print Fibonacci series in C++​,

in first first = 0 second = 1 i =3

``````while(3<=8)
{
next = first+second; //0+1;
cout<<next; // 1
first = second; //1
second = next//1
3++; // 4
}``````

now first =1 , second =1 i =4

``````while(4<=8) {
next = first+second;//1+1
cout<<next;// 2
first = second; // 1
second = next//2
4++; // 5
}``````

now first =1 second =2 i =5

``````while(5<=8) {
next = first+second;//1+2
cout<<next;// 3
first = second; // 2
second = next//3
5++; // 6
}``````

now first = 2 second =3 i =6

``````while(6<=8) {
next = first+second;//2+3
cout<<next;// 5
first = second; // 3
second = next//5
6++; // 7
}``````

now first = 3 second =3 i =7

``````while(7<=8) {
next = first+second;//3+5
cout<<next;// 8
first = second; // 5
second = next//8
7++; // 8
}``````

now first = 5 second = 8 i =8 and in last execution 13 will be print as above manner

in the value of variable i increase by 1 so its become 9 so condition will be such as,

``while( 9<=8)``

which becoming false so loop will be terminate and we get the following output,

``0 1 1 2 3 5 8 13``

Related exercise

C++ Examples

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