#python program to calculate perimeter of a triangle

#take all three sides of triangle as input from user

side1=input("Enter first side of triangle: ")

side2=input("Enter second side of triangle: ")

side3=input("Enter third side of triangle: ")

try:

    side1=float(side1)

    side2=float(side2)

    side3=float(side3)

    #calculate perimeter of triangle

    perimeter = side1 + side2 + side3

    #print perimeter of triangle

    print("---output---")

    print("perimeter of triangle with sides %0.2f,%0.2f,%0.2f is %0.2f"%(side1,side2,side3,perimeter))

except:

    print("---error---")

    print("please enter a valid length")

Enter first side of triangle: 3

Enter second side of triangle: 4

Enter third side of triangle: 5

---output---

perimeter of triangle with sides 3.00,4.00,5.00 is 12.00

 

Enter first side of triangle: a

Enter second side of triangle: b

Enter third side of triangle: 12

---error---

please enter a valid length