find a raise to power of b

def power(a,b):
    res=1
    if b==0:
        return 1
    else:
        for i in range (b):
            res=res*a
    return res
#__main__
print("enter only positive numbers below:")
num=int(input("enter base number:"))
p=int(input("raised to power of:"))
result=power(num,p)
print(num,"raised to power of",p,"is",result)

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factorial

def factorial(n):
    if n<2:
        return 1
    return n*factorial(n-1)
#__main__
n=int(input("enter a number (>0):"))
print("factoriaal of",n,"is",factorial(n))
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gcd

def gcd(a,b):
    if b==0:
        return a
    else:
        return gcd(b,a%b)
#__main__
n1=int(input("enter first number:"))
n2=int(input("enter second number:"))
d=gcd(n1,n2)
print("gcd of",n1,n2,"is",d)
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fibonicci

def fib(n):
    if n==1:
        return 0
    elif n==2:
        return 1
    else:
        return fib(n-1)+fib(n-2)
#__main__
n=int(input("enter last term required:"))
for i in range(1,n+1):
    print(fib(i),end=',')
print("...")

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binary search

def binsearch(ar,key):
    low=0
    high=len(ar)-1
    while low<=high:
        mid=int((low+high)/2)
        if key==ar[mid]:
            return mid
        elif key<ar[mid]:
            high=mid-1
        else:
            low=mid+1
    else:
        return -999
#__main__
ar=[12,15,21,25,28,32,33,36,43,45]
item=int(input("enter search item:"))
res=binsearch(ar,item)
if res>=0:
    print(item,"found at index",res)
else:
    print("sorry!",item,"not found in array")
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