这是我的代码：

#include <stdio.h>
#include <conio.h>

int processChoice()
{
    int choice = -1; //I need to execute this code without using any variable
    printf("\nMake a Choice (1, 2, 3 or 0): ");
    scanf("%d",&choice);
    printf("%d",choice);
    
    switch(choice)
    {
        case 0:
        printf("\nExiting...\n");
        break;
        case 1:
        printf("\nDrawing rectangle...\n");
        break;
        case 2:
        printf("\nDrawing Right triangle...\n");
        break;
        case 3:
        printf("\nDrawing isosceles triangle...\n");
        break;
        
        default:
        printf("\n** Invalid Choice! **\n");
        choice = -1;
    }
    return choice;
}

void showMenu()
{
    printf("\nMenu:");
    printf("\n1. Draw Rectangle");
    printf("\n2. Draw Right triangle");
    printf("\n3. Draw isosceles triangle");
    printf("\n0. Exit program\n");
}

int main()
{
    int x = -1;
    do
    {
        showMenu();
      
    }while(processChoice() != 0);
    return 0;
}

这是我的代码，我在这里使用了一个变量“int Choice = -1;“我应该按照我导师的指导方针执行相同的代码，而不使用任何变量。
我希望在不使用任何变量的情况下执行相同的代码。