Thread: some time to spare?

  1. #1
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    some time to spare?

    I am preparing for programing exams at uni, Could some one please help me with these problems?



    1. Indicate why the following pseudo-code is likely to produce incorrect output.
    Indicate what needs to be done to make it correct.
    Code:
    algorithm summation
    integer count, sum
    begin
          for count  <--1 to 10 do
               sum <-- sum + count
          endfor
          output 'Sum of numbers between 1 & 10 is ',sum
    end algorithm

    2. What is the value of variable i and of variable j on line 6 below? Explain your answer.
    Code:
    1    i=0;j=0;
    2    while (i<10)
    3    {
    4         j=j+2;
    5    }
    6    // What is the value of variable i and variable j?



    3. Explain why the fscanf function has an '&' in front of the variable names for integers, floats, etc. For example, fscanf(input,"&#37;d",&age),and explain why the fscanf function does not have an '&' in front of the variable names for arrays. For example, fscanf(input,"%s",string_array).





    4. Give a pseudo-code example to illustrate how a professional programmer would get a positive integer value from a user. Explain your design decisions.




    5.Give the pseudo-code const and var declarations that could be used to hold information about a student. The information required is their name, address, student number, email address and telephone number.


    6. Give separate fprintf statements that will display :

    i) an integer variable height with a field width of 10
    characters
    ii) a character string stored in variable name
    iii) a double floating point number with a field width of 8, and
    3 decimal places that is in variable weight.
    iv) a literal string "hello world.\nHow are you?"
    v) an integer variable fred using a left-justified format
    in a field width of 8 places.
    Last edited by juststartedC; 11-16-2007 at 04:56 AM.

  2. #2
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    Homework policy

    How about you post what you THINK are the right answers, and then we can comment on ways to improve it?

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  3. #3
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    ok this is what i think: (most likely wrong)

    1. The program hasnt asked the user for any values and it hasnt stored the value. also i think it needs to initialize a value for count

    2. i=0 and j=2

    3. i honestly have no idea about this one.

    4. if value<0 then
    output ' please enter a positive value'
    else
    do....etc

    5. int telephone
    char student-number [7] // since our student numbers have max 7 numbers
    char name []
    char address []
    char email []


    6.

    i) fprintf(output,"%10c", height);

    ii) fprintf(output,"%s", name);

    iii) fprintf(output,"%8.3lf", weight);

    iv)no idea

    v) fprintf(output,"%8d", fred);

  4. #4
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    ok this is what i think: (most likely wrong)

    1. The program hasnt asked the user for any values and it hasnt stored the value. also i think it needs to initialize a value for count
    =====
    No initialization of the var count. No user input needed.

    2. i=0 and j=2
    =====
    i = 0, j = ?? because it's an endless loop. i will always be less than 10 since it doesn't change it's value. j will go to the compiler's highest (or within 1 of that highest) value for that datatype, and then "loop back" to it's lowest value (or lowest value + 1), and start climbing up by two's, from there.

    You're not giving me a trick question before my morning java are you?

    3. i honestly have no idea about this one.
    =====
    scanf() and fscanf() need a pointer (address). Strings are their own base address. Variables whose names are not their own base address, need the address of operator '&' included.

    Arrays of any type include their own base address:

    &ArrayName[0] is the address at the base (first element) address of the array ArrayName.
    ArrayName, by itself, is also the base (first element) address of the array ArrayName.
    Last edited by Adak; 11-16-2007 at 07:40 AM.

  5. #5
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    Thanks a lot adak you are a champ, however, what about questions 4,5,6?

  6. #6
    Beautiful to C Aia's Avatar
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    Quote Originally Posted by juststartedC View Post
    Thanks a lot adak you are a champ, however, what about questions 4,5,6?
    char student-number [7] // since our student numbers have max 7 numbers

    This could be an int student-number
    In fact you'll never will be able to enter 7 digits in char student-number[7]. You forgot that this is a string and it will have a '\0' at the end of it.

    >iv) a literal string "hello world.\nHow are you?"
    fprintf( output, "&#37;s", "hello world.\nHow are you?" );

    >v) an integer variable fred using a left-justified format in a field width of 8 places.
    You wrote: fprintf(output,"%8d", fred); That's right justified. "%-8d" will make it left justified.

    >i) an integer variable height with a field width of 10 characters
    Just another way: fprintf( output, "%*d", 10, height );
    Last edited by Aia; 11-16-2007 at 10:43 PM.

  7. #7
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    Thanks alot aia.

    Regarding
    iv) a literal string "hello world.\nHow are you?"
    fprintf( output, "%s", "hello world.\nHow are you?" );
    wouldnt the \n take it to the nex line thus apearing like this:?

    Hello World
    How are you?

  8. #8
    Beautiful to C Aia's Avatar
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    Quote Originally Posted by juststartedC View Post
    Thanks alot aia.

    Regarding

    wouldnt the \n take it to the nex line thus apearing like this:?

    Hello World
    How are you?
    You could always tested by writing a little piece and compiling it, using printf
    The answer is Yes.

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    so what fprintf statement should i write to display it like this

    Hello world.\nHow are you?


    say if i write it like this :

    fprintf(output,"Hello world.\n\nHow are you?");

    Would it display one and go to the next line for the other \n ???

  10. #10
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    close: \\

  11. #11
    Beautiful to C Aia's Avatar
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    In other disciplines you might learn by asking just questions. No in programming.
    Why don't you compile it and see what it does?
    I am not been rude I am giving you a valuable suggestion.
    In fact why don't you try to display \n in the screen using printf()

  12. #12
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    unfortunately i dont have a compiler, and the person who actually owns this laptop doesnt want me to install one, so i cant try the commands otherwise i would have found out the solution by now, that why im asking some one to help me.

  13. #13
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    Does the laptop have a USB port? put it on the usb memory and run it from there.

  14. #14
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    anyone out there knows what fprintf statement would display exactly the following:

    hello world.\nHow are you?

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