Flow of Execution in a Function Call

☞It refers to the order in which statements are executed during a program run.

☞Program execution begins with first statement of __main__ segment.

Example : 

def  add(a,b):
    c=a+b      #statement 1 of add()
    return c     #statement 2 of add()

num1=int(input("Enter first number : "))        #statement 1 of __main__
num2=int(input("Enter second number : "))  #statement 2 of __main__
result=add(num1, num2)                               #statement 3 of __main__
print("Total=", result)                                      #statement 4 of __main__

Flow of Execution : 

main.1 → main.2 → main.3 → add.1 → add.2 → main.3 → main.4