Question

Create the function fact that had a positive integer argument and returns its factorial . Recall that factorial (n) = 1*2*3***n. For example factorial (4)=1*2*3*4=24, (python)

Answer 1

Factorial is the product of all positive integer which is less than given number is known as factorial of that number for example we can say 24 is the factorial of number 4.

24 = 1*2*3*4;

here i wrote the code in python 3. and after this // i will comment about line and also comment will in green color and code in black color :

def fact(val):    // this is the function declartion with parameter which we want to pass so here i am passing val parameter to this function.
    total=1     // here i take total variable in which i will store factorial value.
    for i in range(1,val+1):     // for loop for factorial calculation here i am taking range 1 to val+1 (where val is the value which we give to calculate factorial ) because 1 will be starting point of for loop but if we give only val as stop point so python will take val - 1 as a stop point so i give val + 1.
        total=total * i     // here our loop will run at val times and it will calcutate factorial
    return total         // now function will return factorial value which is we stored in total.
val = int(input("enter a number"))     // here we are taking user input and storing to val. and here also i added int so it will take only integer value.
print("(",val,") =",end=" ")       // from this line it will print ( val ) =
for i in range(1,val):      // in this loop we will get output of sequence and multiply symbol until value-1 which we will enter.
    print(i,"*",end=" "),
print(val," = ",fact(val))   // now finally we call the function by fact(val) and before this we will print number which we will enter because above for loop print till val -1 and then after function call function give factorial and which will print.