Data type issues

[john3j]

Hello,

I wrote the code for my homework assignment (I did this on my own and am not trying to get someone else to do my homework) and I cannot get it to compute correctly. I am using code::blocks to compile the code for me. I couldnt get the output to display properly, so I am reaching out to see if someone can help me figure out why PI or any of the other variables are not being displayed properly.

I appreciate any help and explanation, as I am a beginner and do not fully understand data types.

Thanks,
John
Here is my code:

/****************************************************************/
/*        CS263 Programming in C                                    */
/*        Assignment #2 Page 182                                    */
/*        Written by: John Strange                                */
/*        Date: 9/5/2012                                            */
/*                                                                */
/*                                                                */
/*   Compute diameter in centimeters of a steel rod,            */
/*   an aluminum rod, and a copper rod which can withstand      */
/*   a particular compression load.                             */
/*                                                                */
/****************************************************************/
/*                                                                */
/*     Defined constants:                                            */
/*                                                                */
/*        steelStress    - 25000                                     */
/*                                                                */
/*        alumStress    - 15000                                     */
/*                                                                */
/*        coppStress    - 20000                                     */
/*                                                                */
/*     Input Variables:                                            */
/*                                                                */
/*        cLoad  - Compression Load                                */
/*                                                                */
/*     Computed Variables:                                        */
/*                                                                */
/*        area  - area                                            */
/*                                                                */
/*        diam  - diameter of rod                                    */
/*                                                                */
/****************************************************************/

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

int main()
{
    const float PI = 3.14159;
    const int steelStress = 25000;
    const int alumStress = 15000;
    const int coppStress = 20000;
    double steelRad, alumRad, coppRad;
    double cLoad, steelArea, alumArea, coppArea;
    double steelDiam, alumDiam, coppDiam;

    printf("Input the compression load:");
    scanf("%d", &cLoad);

    if(cLoad > 0)
    {
        steelArea = cLoad / steelStress;
        alumArea = cLoad / alumStress;
        coppArea = cLoad / coppStress;

        steelRad = sqrt(steelArea / PI);
        alumRad = sqrt(alumArea / PI);
        coppRad = sqrt(coppArea /PI);

        steelDiam = steelRad * steelRad;
        alumDiam = alumRad * alumRad;
        coppDiam = coppRad * coppRad;

        printf("\n\nValue of PI: %d", PI);
        printf("\nCompression Load Value: %d", cLoad);
        printf("\nAluminum Stress Value: %d", alumStress);
        printf("\nSteel Stress Value: %d", steelStress);
        printf("\nCopper Stress Value: %d", coppStress);
        printf("\nAluminum Radius Value: %d", alumRad);
        printf("\nSteel Radius Value: %d", steelRad);
        printf("\nCopper Radius Value: %d", coppRad);
        printf("\nAluminum Area Value: %d", alumArea);
        printf("\nSteel Area Value: %d", steelArea);
        printf("\nCopper Area Value: %d", coppArea);
        printf("\nAluminum Diameter Value: %d", alumDiam);
        printf("\nSteel Diameter Value: %d", steelDiam);
        printf("\nCopper Diameter Value: %d", coppDiam);

        printf("\n\nType of material: Steel");
        printf("\nCompression load: %d", cLoad);
        printf("\nAllowable stress in lbs/m^2: %d", steelStress);
        printf("\nDiameter in centimeters: %d", steelDiam);

        printf("\n\nType of material: Aluminum");
        printf("\nCompression load: %d", cLoad);
        printf("\nAllowable stress in lbs/m^2: %d", alumStress);
        printf("\nDiameter in centimeters: %d", alumDiam);

        printf("\n\nType of material: Copper");
        printf("\nCompression load: %d", cLoad);
        printf("\nAllowable stress in lbs/m^2: %d", coppStress);
        printf("\nDiameter in centimeters: %d", coppDiam);


    }

}

[laserlight]

How exactly does it not work?

By the way, I note that the scanf format specifier for double is not %d

[jimblumberg]

First thing I recommend is to increase your compiler warning level and then fix the warnings the compiler is issuing. Here are the warnings I received when I compiled your code.

main.c||In function ‘main’:|
main.c|48|warning: format ‘%d’ expects argument of type ‘int *’, but argument 2 has type ‘double *’ [-Wformat]|
main.c|64|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|65|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|69|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|70|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|71|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|72|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|73|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|74|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|75|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|76|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|77|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|80|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|82|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|85|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|87|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|90|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
main.c|92|warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘double’ [-Wformat]|
||=== Build finished: 0 errors, 18 warnings ===|

You may want to study the documentation for scanf() and printf() to find the correct format specifiers.

Jim

[john3j]

I have changed the format specifier to %f so there are no issues with float and I changed the data type to floats. The issue is that when I run it the math is not calculated properly. If i enter 2000 for cLoad and steelArea = (cLoad / steelStress) then steelArea should equal 0.08 and not the number listed in the attachment. Here is my updated code.

/****************************************************************/
/*        CS263 Programming in C                                    */
/*        Assignment #2 Page 182                                    */
/*        Written by: John Strange                                */
/*        Date: 9/5/2012                                            */
/*                                                                */
/*                                                                */
/*   Compute diameter in centimeters of a steel rod,            */
/*   an aluminum rod, and a copper rod which can withstand      */
/*   a particular compression load.                             */
/*                                                                */
/****************************************************************/
/*                                                                */
/*     Defined constants:                                            */
/*                                                                */
/*        steelStress    - 25000                                     */
/*                                                                */
/*        alumStress    - 15000                                     */
/*                                                                */
/*        coppStress    - 20000                                     */
/*                                                                */
/*     Input Variables:                                            */
/*                                                                */
/*        cLoad  - Compression Load                                */
/*                                                                */
/*     Computed Variables:                                        */
/*                                                                */
/*        area  - area                                            */
/*                                                                */
/*        diam  - diameter of rod                                    */
/*                                                                */
/****************************************************************/

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

int main()
{
    const float PI = 3.14159;
    const float steelStress = 25000;
    const float alumStress = 15000;
    const float coppStress = 20000;
    float steelRad, alumRad, coppRad;
    float cLoad;
    float steelArea, alumArea, coppArea;
    float steelDiam, alumDiam, coppDiam;

    printf("Input the compression load: ");
    scanf("%f", &cLoad);

    if(cLoad > 0)
    {
        steelArea = (cLoad / steelStress);
        alumArea = (cLoad / alumStress);
        coppArea = (cLoad / coppStress);

        steelRad = (sqrt(steelArea / PI));
        alumRad = (sqrt(alumArea / PI));
        coppRad = (sqrt(coppArea /PI));

        steelDiam = (steelRad * steelRad);
        alumDiam = (alumRad * alumRad);
        coppDiam = (coppRad * coppRad);

        printf("\n\nValue of PI: %f", test);
        printf("\nCompression Load Value: %f", cLoad);
        printf("\nAluminum Stress Value: %f", alumStress);
        printf("\nSteel Stress Value: %f", steelStress);
        printf("\nCopper Stress Value: %f", coppStress);
        printf("\nAluminum Radius Value: %f", alumRad);
        printf("\nSteel Radius Value: %f", steelRad);
        printf("\nCopper Radius Value: %f", coppRad);
        printf("\nAluminum Area Value: %f", alumArea);
        printf("\nSteel Area Value: %f", steelArea);
        printf("\nCopper Area Value: %f", coppArea);
        printf("\nAluminum Diameter Value: %f", alumDiam);
        printf("\nSteel Diameter Value: %f", steelDiam);
        printf("\nCopper Diameter Value: %f", coppDiam);

        printf("\n\nType of material: Steel");
        printf("\nCompression load: %f", cLoad);
        printf("\nAllowable stress in lbs/m^2: %f", steelStress);
        printf("\nDiameter in centimeters: %f", steelDiam);

        printf("\n\nType of material: Aluminum");
        printf("\nCompression load: %f", cLoad);
        printf("\nAllowable stress in lbs/m^2: %f", alumStress);
        printf("\nDiameter in centimeters: %f", alumDiam);

        printf("\n\nType of material: Copper");
        printf("\nCompression load: %f", cLoad);
        printf("\nAllowable stress in lbs/m^2: %f", coppStress);
        printf("\nDiameter in centimeters: %f", coppDiam);


    }

}

Also, when I output the value of the constant PI, it says 0. Any further help to understand my problems would be greatly appreciated! Here is the output when I run the program and enter 2000 for cLoad:

Input the compression load:2000


Value of PI: 0
Compression Load Value: 2000
Aluminum Stress Value: 15000
Steel Stress Value: 25000
Copper Stress Value: 20000
Aluminum Radius Value: -972164833
Steel Radius Value: -1686605182
Copper Radius Value: -296046439
Aluminum Area Value: 1181977184
Steel Area Value: 559379162
Copper Area Value: 886482888
Aluminum Diameter Value: 951150351
Steel Diameter Value: -288303248
Copper Diameter Value: 713362763

Type of material: Steel
Compression load: 2000
Allowable stress in lbs/m^2: 25000
Diameter in centimeters: -288303248

Type of material: Aluminum
Compression load: 2000
Allowable stress in lbs/m^2: 15000
Diameter in centimeters: 951150351

Type of material: Copper
Compression load: 2000
Allowable stress in lbs/m^2: 20000
Diameter in centimeters: 713362763
Process returned 35 (0x23) execution time : 12.935 s
Press any key to continue.

Thanks,
John

[jimblumberg]

After changing the following line:

        printf("\n\nValue of PI: %f", test);

(I replaced test with PI). I got a compile error that test was not defined.

The program produced these results:

Input the compression load: 2000


Value of PI: 3.141590
Compression Load Value: 2000.000000
Aluminum Stress Value: 15000.000000
Steel Stress Value: 25000.000000
Copper Stress Value: 20000.000000
Aluminum Radius Value: 0.206013
Steel Radius Value: 0.159577
Copper Radius Value: 0.178412
Aluminum Area Value: 0.133333
Steel Area Value: 0.080000
Copper Area Value: 0.100000
Aluminum Diameter Value: 0.042441
Steel Diameter Value: 0.025465
Copper Diameter Value: 0.031831

Type of material: Steel
Compression load: 2000.000000
Allowable stress in lbs/m^2: 25000.000000
Diameter in centimeters: 0.025465

Type of material: Aluminum
Compression load: 2000.000000
Allowable stress in lbs/m^2: 15000.000000
Diameter in centimeters: 0.042441

Type of material: Copper
Compression load: 2000.000000
Allowable stress in lbs/m^2: 20000.000000
Diameter in centimeters: 0.031831

Jim

[john3j]

Thanks Jim! For some reason it was just hosed. I created a new project and pasted my code...then it worked just fine. Thank you for testing!