Solution for Exercise 10-1

ex1001

#include <stdio.h>

void prompt();      /* function prototype */

int main()
{
    int loop;
    char input[32];

    loop=0;
    while(loop<5)
    {
        prompt();
        fgets(input,31,stdin);
        loop=loop+1;
    }
    return(0);
}

/* Display prompt */

void prompt()
{
    printf("C:\\DOS> ");
}

Notes

* Two backslashes, \\, are used in the printf() function in Line 24. This expression is required so that a single backslash appears in the output, which is how the old MS-DOS prompt looked:

C:\DOS>

* You could modify Lines 3 and 22 so that the void keyword appears in the empty parentheses. For example, for Line 3:

void prompt(void); /* function prototype */

And Line 22:

void prompt(void)

Whether you choose to do that is up to you. I prefer to use the word void. If the parenthesis are empty, then it looks like I forgot something.

* The input buffer size (input[]) and the size argument of the fgets() function are identical; fgets() won't overflow the buffer when the values are equal. I specified the value 31 (for a 32-character buffer) out of habit. Back in the old days, I was ever so cautious of buffer overflows. (I don't use fgets() to read strings in my own code because it retains the newline.)

* Code::Blocks may report an "ignored return value" warning for the fgets() statement. The function returns a pointer (covered in Chapter 18) or NULL when a string isn't read. That's a possibility, hence the warning message. At this point in your C education, it's okay to ignore the warning.

* By the way, the main() function doesn't lack arguments. These arguments need to be specified only when they're used. Regardless, do not put void in the main() function, as in main(void). This expression is incorrect and the compiler will barf.

Exercise ex1002 →