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Why does fflush(stdin) fail to work ?

 
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Old 09-02-2018
Why does fflush(stdin) fail to work ?
Code:
   #include <stdio.h>
    #include <stdlib.h>
    int main(void)
    {
        double number;
        while (scanf("%lf", &number) != 1)
        {   
            printf("Error\n");
           
        }   
        printf("%lf\n", number);
    
    
        return 0;
    }

Look at the above code.

I want the program to stop for me to type something again every time scanf gets an invalid value.


Never ending loop occurs.

I know the first invalid value has not been cleared and is still in the buffer.

So I use fflush(stdin).

Code:
    #include <stdio.h>
    #include <stdlib.h>
    int main(void)
    {
        double number;
        while (scanf("%lf", &number) != 1)
        {   
            printf("Error\n");
            fflush(stdin);
        }   
        printf("%lf\n", number);
    
    
        return 0;
    }


However, it keeps failing to work.

Why am I wrong and how can I modify the code to make that work?
 
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