Thursday, October 30, 2008

Learning Computer Programming - Page 6

We are now getting a feel of how to tame the computer. Some important notes:
  • The computer is very foolish. It does not understand any other thing except a few words and symbols. Hence, while reading a programming book, use only the words and symbols taught, and do not assume any thing more.
  • The computer does not know what it is doing. It is entirely up to you to write whatever statements you need and get the work done by the computer.
  • We have chosen the names of variables as sum_till_now and next_number, but these could be anything of your choice.
  • Empty lines or spaces in the program is just for the nice look and feel. It does not mean anything to the computer.
Okay. Now, if the problem would have been to add from ¨1 to n, n to be available at the time of execution,¨ the program would be something like:

1. #include <stdio.h>
2. int main()
3. {
4. int sum_till_now = 0;
5. int next_number = 0;
6. int last_number;
7.
8. printf(¨What is the last number?¨);
9. scanf(¨%d¨, &last_number);
10.
11. while (next_number < last_number)
12. {
13. next_number = next_number + 1;
14. sum_till_now = sum_till_now + next_number;
15. }
16.
17. printf(¨The result is %d\n¨, sum_till_now);
18. }

Statement 9 reads a number from input and puts it in the variable last_number. If you execute the program, it will ask for the last_number, which you have to normally type from the key board.

Now that the scanf statement is in your bag, let's attempt a program for adding a few numbers to be input at the time of execution. Program should stop adding and display the result when 0 is input. The program is given below.

1. #include <stdio.h>
2. int main()
3. {
4. int next_number = 1;
5. int sum = -1;
6.
7. while (next_number != 0)
8. {
9. sum = sum + next_number;
10. printf(¨Enter the next number?¨);
11. scanf(¨%d¨, &next_number);
12. }
13.
14. printf(¨The result is %d\n¨, sum);
15. }

Conclusion

You now have got a feel of what programming is and how to tame it. Remember that this was just to show you the approach. You have a long and fascinating way to go. While studying programming, give enough time to understand all the constructs you come across, and never skip a single word from your programming book.

Happy programming! Please post all your queries and feedbacks at http://groups.google.co.in/group/sanjaypatel?hl=en

Please give a little effort to recommend this article to all who need this.

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