import matplotlib.pyplot as plt

print("Stress vs Strain Diagram Maker")

xlist = [0]
ylist = [0]

points_to_graph = 0

while points_to_graph < 4:
   points_to_graph = int(input("How many points you want to graph (at least 4) \n"))

for x in range(points_to_graph):

    stress = float(input("Provide Stress for point {} \n".format(x+1)))
    strain = decimal(input("Provide Strain for point {} \n".format(x+1)))

    ylist.append(stress)
    xlist.append(strain)



print(xlist)
print(ylist)

plt.plot(xlist, ylist)
plt.ylabel('Stress')
plt.xlabel('Strain')
plt.axis([0,5.0, 0, 20])
plt.show()