PROGRAM-1:
Fibonacci series up to n number of terms
#include <stdio.h>
int main()
{
    int i, n, t1 = 0, t2 = 1, nextTerm;
 
    printf("Enter the number of terms: ");
    scanf("%d", &n);
 
    printf("Fibonacci Series: ");
 
    for (i = 1; i <= n; ++i)
    {
        printf("%d, ", t1);
        nextTerm = t1 + t2;
        t1 = t2;
        t2 = nextTerm;
    }
    return 0;
}
 
OUTPUT:
Enter the number of terms: 10
Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 
 
PROGRAM-2: 
Program to generate Fibonacci sequence up to a certain number
#include <stdio.h>
int main()
{
    int t1 = 0, t2 = 1, nextTerm = 0, n;
 
    printf("Enter a positive number: ");
    scanf("%d", &n);
 
    printf("Fibonacci Series: %d, %d, ", t1, t2);
 
    nextTerm = t1 + t2;
 
    while(nextTerm <= n)
    {
        printf("%d, ",nextTerm);
        t1 = t2;
        t2 = nextTerm;
        nextTerm = t1 + t2;
    }
    
    return 0;
}
 
OUTPUT:
Enter a positive integer: 100
Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89,