Help with c programming please

This is a discussion on Help with c programming please within the C Programming forums, part of the General Programming Boards category; Hello all this is my first post. I'm writing a program in 'c' using lcc win32. The program is to ...

  1. #1
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    Mar 2004
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    Help with c programming please

    Hello all this is my first post.

    I'm writing a program in 'c' using lcc win32.

    The program is to perform eulers calculation and store answers in arrays.
    The program is to use pointers, arrays and functions.

    This is the start of my program any help or tips are appreciated.



    #include <stdio.h>
    #include <math.h>

    void calculation (float Y[], float X[], int i, float step_interval)

    {

    i = 0;

    Y[0] = 0;
    Y[0] = 1;

    for (i=0; i<=step_interval; i++)

    {
    Y[i+1] = Y[i] + (step_interval) * (X[i] * (exp, (-X[i])));
    }

    for (i = 0; i <= step_interval; i++)

    {
    printf ("%f, %f", Y[i], X[i]);

    }

    }
    void main()

    {

    float X, Y, step_size, time_interval;
    int num, exp, sum, i;

    printf("\n Please enter the intial conditions of 'x': ");
    scanf("%f", &X);

    printf("\n Please enter the intial conditions of 'y': ");
    scanf("%f", &Y);


    printf("\n Please enter the step size (h): ");
    scanf("%f", &step_size);

    printf("\n Please enter the time interval: ");
    scanf("%f", &time_interval);

    calculation =(X, Y, &step_size, &time_interval);


    printf("\n The value of sum = %f\n\n",calculation);

    }

    Thank You
    Code:
    /code

  2. #2
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    Have you compiled the program? Did the compiler tell you anything? Did you understand what the compiler told you?

    (The compiler is smarter than me; use as much information from him as possible, and get back to us if you need help getting to the next step.)

  3. #3
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    Join Date
    Mar 2004
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    2
    Cheers for reply

    made some changes.

    Still problems with:

    Y[i+1] = calculation(X, Y, step_size, time_interval);

    Comments: The object is to perform eulers equation for the particular
    solution of (x exp -x).

    Eulers equation is y + h (x exp -x)

    h = number of step sizes

    y and x increment by 1 each step size until the user defined
    time interval is reached.


    Errors:

    type error: pointer expexted

    type error in arguement 1 to 'calculation'; found 'float' expected to pointer to float.

    type error in arguement 2 to 'calculation'; found 'float' expected to pointer to float.

    operands of = have illegal types 'float' and 'void'

  4. #4
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    Mar 2004
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    536
    I'm just guessing, since you didn't tell us what changes you made, but:

    You define calculation() with arguments

    float X[], float Y[], etc.

    Now, the compiler sees these as

    float *X, float *Y, etc.

    Thus the message about "expecting pointer to float".

    Your original post showed that you called calculation() with X and Y as arguments, where X and Y were declared as type float in main().

    Does this help?

    Dave

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