Thread: help on program

You're missing some important parts of the assignment. You didn't really ask any questions, but I've bolded what you missed:

Write a C Program to have a char variable. Use printf to print “Press any Key!”. Make sure to print the double quotes as above. Use getch() to input the key pressed. Use puts to Output “You pressed” and putch to output the actual character.

getch() returns the character typed, but you're not capturing it. You're just letting it float away into space, never to be seen again. HINT: You have a char c. Use it.

Pass the character returned by getch() to a putch() call. HINT: The character should be in your variable c if you follow the instructions in the previous paragraph.

He'll definitely run into problems with that printf() syntax. I was actually hoping he'd figure it out on his own, since everything he needed to know to complete this assignment was probably covered in class or was assigned reading.

First off, I'd like to point out, even though this is kinda off topic, you might want to post this in C++ Programming next time.

As for the code, you're very close. Again, you're not printing the quotes in the printf statement. Since " is a special character in the syntax of printf and puts (namely it designates the string to be outputted) you can't simply put another quote down. Here's an example of how your code is being read.

Code:

printf("press any key!\n");

The red text is what is actually being outputted. \n is a special character that is really the same as you pressing the enter key. The dark red quotes are not printed. They simply tell the program that everything between them is a character string. Because the double quote serves this purpose, you can't just put exrta double quotes in there. If you do that, the program will group two separate strings and then you will have problems. Now, since people such as yourself want to output a double quote character, you simply put in \" wherever you want one to be outputted. It is read just like the \n character, except it outputs a double quote instead of going to the next line.

The puts (which stands for put string) is perfectly fine, as I'm sure you know.

However, you don't quite seem to understand how putch (put character) works. Remember, that any function, no matter what, has parenthases, whether it takes arguments or not. So, your first mistake was that you put

Code:

putch;

instead of

Code:

putch();

Secondly, it outputs a character, but you need to tell it what character. If you want it to output the vlue of a character variable, simply put the name of the variable in the parenthases. If you want it to always output the same character, simply put that character inside the parenthases and surround it with a single quote('). Like so.

Code:

char variable;
putch(variable);

Code:

putch('a');

You think you get it now? I hope I didn't ramble too much.

Your assignment is to print "Press any key!" INCLUDING the quotes.

Code:

printf("Press any key!\n"); /* outputs: Press any key! */
/* however */
printf("\"Press any key!\"\n"); /* outputs: "Press any key!" */

Why this happens is explained in Jaken Veina's post above [edit]and now below[/edit].

Okay, let me explain exactly what the quotes do. A single quote MUST BE BEFORE AND AFTER a character. (not yelling at you, just conveying that it's important) To the computer, 'a' means the character a. The same goes for double quotes, except they tell the computer it is a string of characters. Therefore the character ' " ' DOES NOT EXIST.

Let's say you wanted to output a double quote and a double quote only. The way you're thinking, you would do this.

Code:

putch('"');
//if you can't tell, that's a double quote surrounded by single quotes

But, as I said, that character doesn't exist.

Now, look for a second at the character '\n'. Notice I have single quotes around that. But that's a string with the characters '\' and 'n', right? Nope. '\n' is a SINGLE CHARACTER. When it's read by printf, putch, or puts, it tells the computer not to display \n at the terminal, but to go to the next line.

The same thing goes for a double quote. Since " has a special function in designating a string, you can't simply put ""Hello"" to output the string Hello in quotes. Here's how the computer would read it.

Code:

printf(""Hello"");

It reads that there are two separate character strings (with nothing in them) and in between them is gibberish. Undoubtedly, you will get a compiler error if you do that.

So, like with '\n' there is a special character for outputing an actual double quote. That character is \". When the computer reads the \" character, instead of saying, "Oh, a character string is beginning", it says, "Oh, the user wants me to output a double quote."

Think you can figure it out now. If not, I can show you how to do it, but I'm really not prone to simply telling people the answer.

EDIT: Ahh, I see someone has already explained it. Oh, well. If you still don't get it, I have another idea for explaining it.