SPEAKER: Let's write a program that tries to copy two strings. I've already gotten started by first printing out "Say something." I next call GetString, storing the return value in s. And then I make sure that s is not null. 

Let's next make our copy of S. I'm going to declare a new variable, t, and store in it s. I'm next going to claim, with printf, that I'm going to capitalize that copy. I'm next going to check that t is at least greater than 0 in length so that I don't accidentally try to capitalize a letter that's not there. Once I'm sure, I'm going to change the value at t bracket 0 to be the return value of toupper, a function that converts its input to uppercase, passing in as its input t bracket 0. 

Lastly, I'm going to print out what the original value was, which, of course, was s. And then I'm going to print what the value of the copy is, which is t. 

When I now compile and run this program, I hope to see my original input followed by a copy thereof with only the copy capitalized. But let's check. Make copy 0, ./ copy 0. And I'll provide an input of, say, hello, but in all lowercase, and then hit Enter. 

Unfortunately, it seems that both the original and the copy are now "Hello" with a capital H. But that's clearly not what I typed. So apparently, when I capitalized t, I somehow capitalized s, even though I thought I was making a copy of s and calling it t. Surely, something here is wrong. But how can we fix?