Interesting problem using printf & scanf only...

Question

I'm running out of ideas for my "Beginning C" class, and the only topics I've discussed so far are Data types, Variables & the printf & scanf functions.

My last quizzes involved simple formulas (area of a circle, volume of a cube..) enclosed inside the printfs..

eg. printf("volume = %d",length * width * height);

I'm looking for something more interesting using only printfs and scanfs :(

Update~ Just to clarify: My students don't know how to use conditional statements and iterative statements yet. It's only week 2, and this is their very first programming class :'( And yes, they can only retrieve the input, then modify it in some way before they output it in the console. I can play with escape sequences (create a box asterisks) or format specifiers (a 3 precision division operation) but that's it..

Answer 1

How about a base-converter. In other words, prompt for a number in decimal and a number system (say, 2 for binary or 16 for hex) and then output the number in that system.

Answer 2

Using only printfs and scanfs, and nothing more? You can only retrieve input and output the input if that's the case.

I don't think that's what you meant though...

Math/Algorithm Related

• Generate/Output the first N prime numbers
• Calculate factorial(n) recursively/iteratively
• Use C as a tool to Find a formula for sum of alternating sums up to positive N

Game Related

• Write a simple character based pong game (single player)
• Write "nibbles" a.k.a "snake" (char based)

Answer 3

• Write a program that asks the user their name, age, and favorite letter of the alphabet.
• Print a single sentence containing all the information.
• Bonus: Print a sentence containing the first letter of their name.

Answer:

char name[50];
int age;
char letter;

printf( "\nWhat is your name? " );
scanf( "%s", name );

printf( "\nHow old are you? " );
scanf( "%d", &age );

printf( "\nWhat is your favorite letter of the alphabet? " );
scanf( " %c", &letter ); //skipping whitespace

printf( "\n\n-------------------\n\n");
printf( "Your name is %s, you are %d years old, and your favorite letter of the alphabet is %c.\n", name, age, letter );

printf( "The first letter of your name is %c", name[0] );

If you'd like some math in there, ask them questions like:

• Write a program that asks the user how many weeks until christmas, then print out how many seconds there are until christmas (given the number of weeks entered only).

Answer 4

I have used a unit converter previously.

• Convert temperatures to and from Celsius, Fahrenheit, and Kelvin.
• Change the base as mentioned by Alex.
• Cooking weights and measures has lots of interesting conversions.