Solution for Exercise 19-12

ex1912

#include <stdio.h>

int main()
{
    char sample[] = "From whence cometh my help?\n";
    char *ps = sample;

    while(*ps != '\0')
    {
        putchar(*ps);
        ps++;
    }
    return(0);
}

Notes

* Unlike Listing 19-6 in the book, you don't need the index variable to make the code work; the ps pointer itself acts as an index.

* In Line 6 the pointer variable ps is created and assigned the address of the string variable sample.

* A while loop is used to work through the string, similar to the code in Listing 19-6. The while loop could have been written to use the index variable, in which case it could look like this:

while(*(ps+index) != '\0') { putchar(*(ps+index)); index++; }

The while loop as written in my solution (top) is cleaner.

*Refer to Table 19-2 (in the book) if you need a review on the *(a+n) format, but that defeats the purpose; the pointer itself is the index you can use to march through a string.

* The while loop's statements could theoretically be combined into a single statement:

putchar(*ps++);

Grant yourself extra For Dummies bonus points if you came up with that solution.

* By the way, the putchar(*ps++); construction is still possible by using array notation, but it's terrifically ugly.

Exercise ex1913 →