CS1101C Lab 2 (Odd Week)

Triangular Numbers

The deadline for this lab question is Friday 02 March 2007, 23:59:59 hours.

The name of your C program file must be called triangular1.c, files with any other name will not be marked.

Preliminary

Every triangular number can be written as the sum:

1 + 2 + 3 + ... + n

for some natural number n. The sequence of triangular numbers for n = 1, 2, 3... is:

1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...

Your Task

Write a program called triangular1.c that prompts the user to input an integer x. If x is a triangular number, display it. If x is not a triangular number, display the nearest triangular number below x and the nearest triangular number above x.

Keep prompting the user to enter an integer until the user chooses to quit the program by entering a value of 0. When the user quits the program, display the number of integers entered, as well as the number of triangular and non-triangular numbers.

Sample Runs

Assuming that the executable is triangular1, a sample run of the program is shown below, which you must follow precisely. User input is denoted in bold.

$ gcc -Wall triangular1.c -o triangular1
$ ./triangular1
Enter an integer (1 - 2000000000, 0 to quit): 1
1 is a triangular number.

Enter an integer (1 - 2000000000, 0 to quit): 2
2 is between triangular numbers 1 and 3.

Enter an integer (1 - 2000000000, 0 to quit): 97
97 is between triangular numbers 91 and 105.

Enter an integer (1 - 2000000000, 0 to quit): 45
45 is a triangular number.

Enter an integer (1 - 2000000000, 0 to quit): 46
46 is between triangular numbers 45 and 55.

Enter an integer (1 - 2000000000, 0 to quit): 1999996635
1999996635 is a triangular number.

Enter an integer (1 - 2000000000, 0 to quit): 2000000000
2000000000 is between triangular numbers 1999996635 and 2000059881.

Enter an integer (1 - 2000000000, 0 to quit): 0
Number of integers entered: 7
Triangular numbers: 3
Non-triangular numbers: 4
Thank you for using my program. Goodbye!

$

Points to Note

Remember to include the program header in your C program file.
For simplicity, we assume that user input will always be within the range of permissible values, so there is no need to perform any explicit checks on the data entered by the user. You may assume that the number entered is always an integer between 0 to 2,000,000,000 inclusive.
Do not use any other data types except int. That means you are not allowed to use double, float, char, etc. or any unsigned types. You are only allowed to use the int data type and nothing else.
Do not use any break, continue, or goto statements.
Do not use any functions from the math library.
Do not use any arrays or pointers.

This document, index.html, has been accessed 26 times since 25-Jun-24 11:57:13 +08. This is the 1st time it has been accessed today.

A total of 18 different hosts have accessed this document in the last 445 days; your host, nsrp-source.comp.nus.edu.sg, has accessed it 7 times.

If you're interested, complete statistics for this document are also available, including breakdowns by top-level domain, host name, and date.