# Author: Jan-Niclas Loosen
# Matrikelnummer: 1540907

# AUFGABE 0
def pi(run=1000):
    return 4 * pi_quarter(run)


def pi_quarter(run=1000):
    ret = 1
    for i in range(run):
        add = 3 + i*2
        if i%2 == 0:
            ret -= 1 / add
        else:
            ret += 1 / add
    return ret


# example for main routine
print("pi/4: "+str(pi_quarter()))
print("pi: "+str(pi())+"\n")


# AUFGABE 02
def convert_to_f(deg):
    return round(deg * (9/5) + 32, 2)


def convert_to_c(deg):
    return round((deg-32) * (5/9), 2)


def dialog():
    deg = input("Degrees: ")
    mode = input("convert to fahrenheit (0) or convert to celsius (1): ")
    try:
        if mode == "0":
            print(str(convert_to_f(float(deg))) + "\n")
        elif mode == "1":
            print(str(convert_to_c(float(deg))) + "\n")
        else:
            print("invalid mode\n")
    except Exception:
        print("invalid input\n")


# example for main routine
again = input("convert (1) or exit (other inputs): ")
while again == "1":
    dialog()
    again = input("convert (1) or exit (other inputs): ")