Thread: Sentinel control is not working

  1. #1
    Registered User
    Join Date
    Oct 2012
    Posts
    3

    Sentinel control is not working

    Essentially my program became an infinite loop and I don't know how to fix this. I want this program to repeatedly ask the user to enter a wattage until the user inputs -1.


    Code:
                                                                                   #include <stdio.h>
    int main()
    {
    
    int wattage, brightness, n;
    
    printf("Enter the wattage (-1 to quit):\n");
    scanf("%d", &wattage);
    
    while(n!=-1)
    {
    switch(wattage/10)
    {
    
    case 2:  printf("Brightness = 125\n"); break;
    
    case 3:  printf("Brightness = 215\n"); break;
    
    case 4:  printf("Brightness = 500\n"); break;
    
    case 5:  printf("Brightness = 880\n"); break;
    
    case 6:  printf("Brightness = 1000\n"); break;
    
    case 7:  printf("Brightness = 1675\n"); break;
    
    default: printf("\nAn invalid wattage was entered!");
    
    
    n++;
    }
    printf("Enter the wattage (-1 to quit):\n");
    scanf("%d", &wattage);
    
    }
    return 0;
    }


    Thank you, in advance

  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
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    > while(n!=-1)
    You're inputting wattage, but testing n ?

    Maybe you should test wattage != -1 instead.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

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