Thread: Whats wrong w/ my loop?? Please help?

  1. 05-29-2002 #1
    aspand
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    Whats wrong w/ my loop?? Please help?

    Hey Guys,
    This is my function..when I put in 'b' or 'c' or 't' it works just fine..type in 'j' and the output looks like this..Why is it doing that..help please! Thanks
    Aspan

    Output:
    What kind of car would you like to park?
    (C)ar or (B)us or (T)ruck:j
    What kind of car would you like to park?
    (C)ar or (B)us or (T)ruck:
    What kind of car would you like to park?
    (C)ar or (B)us or (T)ruck:

    CODE:
    char inputCar(void)
    {

    char c;
    char car;


    printf("What kind of car would you like to park?\n");
    printf("(C)ar or (B)us or (T)ruck:");
    scanf("%c", &car);
    c = toupper(car);

    while(!(c == 'C' || c == 'B' || c == 'T'))
    {
    printf("What kind of car would you like to park?\n");
    printf("(C)ar or (B)us or (T)ruck:\n");
    scanf("%c", &car);
    c = toupper(car);
    }


    return c;
    }
  2. 05-29-2002 #2
    Spark
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    What happens if you fflush() the stdin after each scanf()? Maybe it interprets the "enter" as another key or something like that? =) Actually I have no clue so it's just a thought.
  3. 05-29-2002 #3
    Sebastiani
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    The problem is not you. It's with scanf(). Try getting it as a string with fgets, then either use strstr(), !strmp(), or extract the char from the string and compare as you did. The code below worked.

    Code:
    

char inputCar(void) 
{
char c; 
char car[5];

do{

printf("What kind of car would you like to park?\n"); 
printf("(C)ar or (B)us or (T)ruck:\n"); 
fgets(car, 5, stdin);
c = toupper(car[0]);

}while(c != 'C' && c != 'B' && c != 'T');

return c; 
}
    Code:
    #include <cmath>
#include <complex>
bool euler_flip(bool value)
{
    return std::pow
    (
        std::complex<float>(std::exp(1.0)), 
        std::complex<float>(0, 1) 
        * std::complex<float>(std::atan(1.0)
        *(1 << (value + 2)))
    ).real() < 0;
}
  4. 05-29-2002 #4
    Sebastiani
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    Sparks suggestion worked.

    Code:
    

char inputCar(void) 
{
char c; 
char car;

do{
fflush(stdin);
printf("What kind of car would you like to park?\n"); 
printf("(C)ar or (B)us or (T)ruck:\n"); 
scanf("%c", &car);
c = toupper(car);
}while(c != 'C' && c != 'B' && c != 'T');

return c; 
}
    Code:
    #include <cmath>
#include <complex>
bool euler_flip(bool value)
{
    return std::pow
    (
        std::complex<float>(std::exp(1.0)), 
        std::complex<float>(0, 1) 
        * std::complex<float>(std::atan(1.0)
        *(1 << (value + 2)))
    ).real() < 0;
}
  5. 05-30-2002 #5
    Hammer
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    What happens if you fflush() the stdin after each scanf()? Maybe it interprets the "enter" as another key or something like that? =) Actually I have no clue so it's just a thought.
    Sparks suggestion worked.
    fflush(stdin) is bad coding. This only gets highlighted like, once a day!

    Use a portable solution like:
    Code:
    ...
scanf("%c", &car);
while (getchar() != '\n');
...
    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]
  6. 05-30-2002 #6
    Spark
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    Originally posted by Hammer


    fflush(stdin) is bad coding. This only gets highlighted like, once a day!
    Damn, I knew my book about C/C++ would be crap.

    This is how the author suggests to do keyboard input:

    Code:
    printf( "Please enter two numbers: ");
scanf( "%d %d", &num1, &num2);
fflush( stdin );
    Lucky me that I didn't actually read this book.
  7. 05-30-2002 #7
    Hammer
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    Lucky me that I didn't actually read this book.
    Burn it.... burn it now!!!
    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]
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