 ### Program 19:To print Fibonacci Series.

Program 19:                                                                                         What is fibonacci series?
```#include<stdio.h>
main()
{
int a=0,b=1,num,c,count;
printf("Enter a number to obtain fibonacci series\n");
scanf("%d",&num);
printf("The series is\n");
printf("%d \n%d\n",a,b);
count=2;
while(count<num)
{
c=a+b;
a=b;
b=c;
printf("%d\n",c);
count++;
}
}```
Explanation:
1. The program starts with intializing
• a - for storing starting number of series
• b - for storing second number of series
• num- for storing the length of series
• c - for temporary(auxiliary) variable
• count-for storing the number of iterations that the loop has undergone
2. First we print the first two values of series i.e. a and b Now the series is 0,1 before starting fibonacci series
3. Now the count is stored with value 2(count=2)
4. The while loop iterates until the count is less than given number num(lenght of series)
• step-1 : Now if num=8(say) ,count=2,a=0,b=1 .
• step-2 : as count is less than count (2 is less than 8 )→ true
• c=0+1=1 → c=1
• a=b → a=1
• b=c → b=1
• Then c is printed and now series is 0,1,1
• Then count is incremented → count=3
• Now values are c=1,a=1,b=1,count=3
• step-3 : as count is less than count(3 is less than 8 ) → true
• c=a+b=1+1→ c=2
• a=b → a=1
• b=c → b=2
• Then c is printed and now series is 0,1,1,2
• Then count is incremented → count=4
• Now values are c=2,a=1,b=2,count=4
• step-4 : as count is less than count(4 is less than 8 ) → true
• c=a+b=1+2→ c=3
• a=b → a=2
• b=c → b=3
• Then c is printed and now series is 0,1,1,2,3
• Then count is incremented → count=5
• Now values are c=3,a=2,b=3,count=5
• step-5 : as count is less than count(5 is less than 8 ) → true
• c=a+b=2+3→ c=5
• a=b → a=3
• b=c → b=5
• Then c is printed and now series is 0,1,1,2,3,5
• Then count is incremented → count=6
• Now values are c=5,a=3,b=5,count=6
• step-6 : as count is less than count(6 is less than 8 ) → true
• c=a+b=3+5→ c=8
• a=b → a=5
• b=c → b=8
• Then c is printed and now series is 0,1,1,2,3,5,8
• Then count is incremented → count=7
• Now values are c=8,a=5,b=8,count=7
• step-7 : as count is less than count(7 is less than 8 ) → true
• c=a+b=5+8→ c=13
• a=b → a=8
• b=c → b=13
• Then c is printed and now series is 0,1,1,2,3,5,8,13
• Then count is incremented → count=8
• Now values are c=13,a=8,b=13,count=8
• step-8: as count is not less than count(8 is less than 8 ) → false
• So the final series is 0,1,1,2,3,5,8,13.
Output: 