C/C++ :: Looping Entire Block Of Code

I just want my program to run continuously until someone enters 0 to exit it. I tried doing while(x=1) and looping my entire block of code. Also there is a switch one is a for one is a while loop both doing the same function. I have basic error checking and whatnot.

/*This is a program that gets a user to input a starting and ending value.
The code then prints the number ie 1 and 5 would be (1,2,3,4,5) and all the squares and cubes.
There is a case statement asking weather you want to run it as a for or as a while loop.
The choices are case sensitive.
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>//allows for power and cube function
int x;
int main(){

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