Speed calculating algorithm?

Hey guys,

I want to make a simple program which calculates speed, distance and time.

This is the code I used:

a=input("1)Find speed\n2)Find distance\n3)Find time\n4)Quit\n")

while a!=4:
    if a==1:
        d=input("\nEnter distance: ")
        t=input("Enter time: ")
        print ("Speed: "+str(d/t)+"\n")
    elif a==2:
        s=input("\nEnter speed: ")
        t=input("Enter time: ")
        print ("Distance :"+str(s*t)+"\n")
    elif a==3:
        s=input("\nEnter Speed: ")
        d=input("Enter distance: ")
        print ("Time :"+str(d/s)+"\n")
    a=input("1)Find speed\n2)Find distance\n3)Find time\n4)Quit\n")

But, my question is, can't it be done like this:

s=input("Speed: ")
d=input("Distance: ")
t=input("Time: ")

#Considering 1- is the symbol for 'find'

s=d/t
if(s==1-):
    print (s)
elif(d==1-):
    print (d)
elif(t==1-):
    print (t)

Won't Python itself decide that in if else case 2, since speed and time are provided, it has to calculate time using formula 's=d/t'?

Thanks

[Lardmeister]

Assuming you are using Python2, you could do it like this:

print("Enter zero for the value you are looking for:")

s = d = t = 0

while True:

    s = input("Speed (miles/hour): ")
    d = input("Distance (miles): ")
    t = input("Time (hours): ")

    if s == 0:
        s = d/float(t)
        f = "You have gone %.3f miles in %.3f hours, speed = %.3f"
        print f % (d, t, s)
    if d == 0:
        d = s * float(t)
        f = "You have gone at %.3f miles/h for %.3f hours, distance = %.3f"
        print f % (s, t, d)
    if t == 0:
        t = d/float(s)
        f = "You have gone %.3f miles at %.3f miles/h, time = %.3f"
        print f % (d, s, t)
    
    yn = raw_input( "Any more calculations (y or n)? ")
    if 'n' in yn.lower():
        break

[shadwickman]

By putting "s = d / t" before the conditionals would only calculate speed - but what happens when you give speed and distance for example? It wouldn't calculate time. You have to put each individual case within the appropriate conditional branch like Lardmeister did.

P.S. This kind of program is much more useful for something like cosine law, sine law, quadratic formula, etc. as opposed to the simplistic s = d / t which is just a simple, one-step calculation :P

[Ene Uran]

@sravan953
also remember that in Python2 ' /' is an integer division by default.
For instance 12/15 gives you a zero. This has changed in Python3.

[vegaseat]

Something like Lardmeister's code would be a good start of an Equation Solver as set forth in:
http://www.daniweb.com/forums/post159522-7.html
Just make sure you keep your units of measurement correct.

[Hi]

help me how do i make a program that will do find the time wether you put o.5 hours or 1 hour because i can't make a program that does both

[Dani]

Welcome to DaniWeb, Hiiiii!! Please post your question as a new thread instead of hijacking this seven year old discussion. It seems you missed where it said "This question has already been answered. Start a new discussion instead." ... Also, please be sure to show what you've done so far and where you're stuck. We won't just do your homework for you.

[thelaga]

I need help to write a python script about the calculation of speed for my school's assignment and I have no idea of how to do it as this is my first year of learning it.

[Smartfitness33]

Speed is separation isolated when taken. For instance, a vehicle ventures 30 kilometers in 2 hours. Its speed is 30 ÷ 2 = 15km/hr

[Smartfitness33]

To illuminate for speed or rate utilize the equation for speed, s = d/t which means speed approaches separation partitioned by time. To fathom for time utilize the equation for time, t = d/s which means time approaches separation partitioned by speed.