Python Drawing Pie Chart/Bar Graph using while loop

I'm having difficulty starting a while loop trying to generate a program that will generate a pie chart or bar graph from numbers that a user will input. How does the while loop need to be written so it's not looping forever? I know I could use a for loop for a finite sequence but i'm not too experienced in that. any guidance would be helpful!

from SimpleGraphics import *

print("Chart Menu: 1.Pie Chart, 2.Bar Chart")

chart = int(input("enter either 1 for pie chart or 2 for bar chart:"))

if chart == 1:

 title = input("Enter the title of the chart: ")

 numSec = int(input("Enter the number of sectors: "))

 tSum = int(input("Enter the total sum of all sector values:  "))

 gsize = int(input("Ehter the grid size (Between 10 and 400): "))

 yLabel = input("Enter the label for the Y-Axis:")

while loop

-the name of each sector

-the value each sector

-draw pie chart

if chart == 2:

title = input("Enter the title of the chart: ")

numCat = int(input("Enter the number of categories: "))

grid = int(input("Ehter the grid size (Between 10 and 400): "))

while loop

-name of each category

-value for that category

-draw bar graph