Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Sirus]

'Cause I'm panicking because this thing is due in 10 minutes.

I want to program, dammit! What' wrong with me, why can't I get this? 

[Max White]

Relax. Logic is a cool, calm and collected thing. We also have a theory called GIGO, that means Garbage In = Garbage Out. It has a secondary, technical meaning, but who cares about that? The point of it is that if your mind is scattered and not logical, your code will be scattered and not logical. Zen the fuck out.

[fergus]

A pointer (e.g. float*) is the address of a piece of data. Dereferencing the pointer means going to that address and using whatever happens to be there.

Also, I just noticed that you didn't initialise you variables, leaving them in an undefined state (i.e. random garbage). I think the problem is that calculate is not setting the outside copy of the variable, leaving them undefined. There might also be something funny going on with scanf.

EDIT: Put printf statements before and after each function call for every variable it's supposed to modify. That should help narrow it down.

EDIT 2: OK, scanf is supposed to take pointers, so that part should be fine.

[Xegeth]

Maybe try posting the code you have now. I'd guess one problem is that calculate is not working as it should. You need to dereference each pointer in calculate, which means looking at the value pointed. Try something like this (and remember to update the declaration if you changed it).

Code: [Select]

void calculate(float* subTotal, int* quantity, float* unitPrice, float* discountAm, float* discountRate, float* subTaxable, float* taxAm, float* total)
{
//Calculations
(*subTotal)    =(*quantity) * (*unitPrice);
(*discountAm)  = (*subTotal) * (*discountRate) / 100.0;
(*subTaxable)  = (*subTotal) - (*discountAm);
(*taxAm) = (*subTaxable) * TAX_RATE/ 100.00;
(*total) = (*subTaxable) + (*taxAm);

return;
}

[Max White]

Spoiler (click to show/hide)

Noise generator is looking good.

[Sirus]

I'll work on it more tomorrow, after a good night's sleep. I just submitted what I had. I'm thinking that a partial assignment is better than no assignment at all.

Here's the code I submitted:

Spoiler (click to show/hide)

Code: [Select]

#include <stdio.h>

#define TAX_RATE 8.50

//Function Declarations
void getData(int*, float*, float*);
void calculate(float, int, float, float, float, float, float, float);
void outputData(int quantity, float unitPrice, float subTotal, float discountAm, float subTaxable, float taxAm, float total);

int main (void)
{
// Local Declarations
int    quantity;

float  discountRate;
float  discountAm;
float  unitPrice;
float  subTotal;
float  subTaxable;
float  taxAm;
float  total;

// Statements
getData(&quantity, &unitPrice, &discountRate);
calculate(&subTotal, &quantity, &unitPrice, &discountAm, &discountRate, &subTaxable, &taxAm, &total);
outputData(quantity, unitPrice, subTotal, discountAm, subTaxable, taxAm, total);

return 0;
} // main

void getData(int *quantity, float *unitPrice, float *discountRate)
{
//Statements
printf("\nEnter number of items sold:         ");
scanf("%d", quantity);

printf("Enter the unit price:               ");
scanf("%f", unitPrice);

printf("Enter the discount rate (per cent): ");
scanf("%f", discountRate);

return;
}

void calculate(float subTotal, int quantity, float unitPrice, float discountAm, float discountRate, float subTaxable, float taxAm, float total)
{
//Calculations
subTotal    = quantity * unitPrice;
discountAm  = subTotal * discountRate / 100.0;
subTaxable  = subTotal - discountAm;
taxAm = subTaxable * TAX_RATE/ 100.00;
total = subTaxable + taxAm;

return;
}

void outputData(int quantity, float unitPrice, float subTotal, float discountAm, float subTaxable, float taxAm, float total)
{
//Statements
printf("\nQuantity sold:       %6d\n", quantity);
printf("Unit Price of items: %9.2f\n", unitPrice);
printf("                     ------------\n");

printf("Subtotal :           %9.2f\n", subTotal);
printf("Discount:           -%9.2f\n", discountAm);
printf("Discounted total:    %9.2f\n", subTaxable);
printf("Sales tax:          +%9.2f\n", taxAm);
printf("Total sale:          %9.2f\n", total);
}

And now, I think I will go to bed. Maybe inspiration will strike while I sleep; it's happened before.

[eerr]

Spoiler (click to show/hide)

I'll work on it more tomorrow, after a good night's sleep. I just submitted what I had. I'm thinking that a partial assignment is better than no assignment at all.

Here's the code I submitted:

Code: [Select]

#include <stdio.h>

#define TAX_RATE 8.50

//Function Declarations
void getData(int*, float*, float*);
void calculate(float, int, float, float, float, float, float, float);
void outputData(int quantity, float unitPrice, float subTotal, float discountAm, float subTaxable, float taxAm, float total);

int main (void)
{
// Local Declarations
int    quantity;

float  discountRate;
float  discountAm;
float  unitPrice;
float  subTotal;
float  subTaxable;
float  taxAm;
float  total;

// Statements
getData(&quantity, &unitPrice, &discountRate);
calculate(&subTotal, &quantity, &unitPrice, &discountAm, &discountRate, &subTaxable, &taxAm, &total);
outputData(quantity, unitPrice, subTotal, discountAm, subTaxable, taxAm, total);

return 0;
} // main

void getData(int *quantity, float *unitPrice, float *discountRate)
{
//Statements
printf("\nEnter number of items sold:         ");
scanf("%d", quantity);

printf("Enter the unit price:               ");
scanf("%f", unitPrice);

printf("Enter the discount rate (per cent): ");
scanf("%f", discountRate);

return;
}

void calculate(float subTotal, int quantity, float unitPrice, float discountAm, float discountRate, float subTaxable, float taxAm, float total)
{
//Calculations
subTotal    = quantity * unitPrice;
discountAm  = subTotal * discountRate / 100.0;
subTaxable  = subTotal - discountAm;
taxAm = subTaxable * TAX_RATE/ 100.00;
total = subTaxable + taxAm;

return;
}

void outputData(int quantity, float unitPrice, float subTotal, float discountAm, float subTaxable, float taxAm, float total)
{
//Statements
printf("\nQuantity sold:       %6d\n", quantity);
printf("Unit Price of items: %9.2f\n", unitPrice);
printf("                     ------------\n");

printf("Subtotal :           %9.2f\n", subTotal);
printf("Discount:           -%9.2f\n", discountAm);
printf("Discounted total:    %9.2f\n", subTaxable);
printf("Sales tax:          +%9.2f\n", taxAm);
printf("Total sale:          %9.2f\n", total);
}And now, I think I will go to bed. Maybe inspiration will strike while I sleep; it's happened before.

Pffft, you still need an immense increase in your pointer-fu. What are you gonna do, figure it all out in your sleep?

[fergus]

OK, I took a copy of the source code, and I think I got it working, so:
1:change

Code: [Select]

void calculate(float subTotal, int quantity, float unitPrice, float discountAm, float discountRate, float subTaxable, float taxAm, float total)
to

Code: [Select]

void calculate(float* subTotal, int* quantity, float* unitPrice, float* discountAm, float* discountRate, float* subTaxable, float* taxAm, float* total)
(the *'s make the variables into pointers

3:put * in-front of all variable references in calculate
i.e.:

Code: [Select]

*subTotal    = *quantity * *unitPrice;
*discountAm  = *subTotal * *discountRate / 100.0;
*subTaxable  = *subTotal - *discountAm;
*taxAm = *subTaxable * TAX_RATE/ 100.00;
*total = *subTaxable + *taxAm;
The *'s are dereferencing operators.

Also, what compiler are you using, mine(gcc) generated several errors when I tried to compile it.

[Sirus]

Can't fucking sleep -_-

I'm using Microsoft Visual Studio 2010. Did your changes, build failed.

[fergus]

Error message?

EDIT: This is the source I have open here:

Spoiler (click to show/hide)

Code: [Select]

#include <stdio.h>

#define TAX_RATE 8.50

//Function Declarations
void getData(int*, float*, float*);
void calculate(float*, int*, float*, float*, float*, float*, float*, float*);
void outputData(int,float,float,float,float,float,float);

int main (void)
{
// Local Declarations
int    quantity;

float  discountRate;
float  discountAm;
float  unitPrice;
float  subTotal;
float  subTaxable;
float  taxAm;
float  total;

// Statements
getData(&quantity, &unitPrice, &discountRate);
calculate(&subTotal, &quantity, &unitPrice, &discountAm, &discountRate, &subTaxable, &taxAm, &total);
outputData(quantity, unitPrice, subTotal, discountAm, subTaxable, taxAm, total);

return 0;
} // main

void getData(int *quantity, float *unitPrice, float *discountRate)
{
//Statements
printf("\nEnter number of items sold:         ");
scanf("%d", &*quantity);

printf("Enter the unit price:               ");
scanf("%f", &*unitPrice);

printf("Enter the discount rate (per cent): ");
scanf("%f", &*discountRate);

return;
}

void calculate(float* subTotal, int* quantity, float* unitPrice, float* discountAm, float* discountRate, float* subTaxable, float* taxAm, float* total)
{
//Calculations
*subTotal    = *quantity * *unitPrice;
*discountAm  = *subTotal * *discountRate / 100.0;
*subTaxable  = *subTotal - *discountAm;
*taxAm = *subTaxable * TAX_RATE/ 100.00;
*total = *subTaxable + *taxAm;

return;
}

void outputData(int quantity, float unitPrice, float subTotal, float discountAm, float subTaxable, float taxAm, float total)
{
//Statements
printf("\nQuantity sold:       %6d\n", quantity);
printf("Unit Price of items: %9.2f\n", unitPrice);
printf("                     ------------\n");

printf("Subtotal :           %9.2f\n", subTotal);
printf("Discount:           -%9.2f\n", discountAm);
printf("Discounted total:    %9.2f\n", subTaxable);
printf("Sales tax:          +%9.2f\n", taxAm);
printf("Total sale:          %9.2f\n", total);
}



Also, I made both of those changes + the "void outputData();" to "void outputData(int,float,float,float,float,float,float);" change from the source code you posed originally.

[Sirus]

There's a bunch of them, all located in the calculate statement.

'function' : cannot convert from 'float *' to 'float'

[Siquo]

Wonder if anyone here has any experience with this....

Looked into Lua like you, thought hey this could be fun, then went on to do different stuff.

So if you find anything, let us know and share your experience

[MaximumZero]

So, I'm thinking about trying to become a lead designer for some games company. I'm not terribly good with code, as my posts will show, but I'm very creative and good with English. Is there a better/more suitable position for me, and if not, what should I focus on in my studies?

[fergus]

OK, I just used diff to check the changes I made to the original source you posted and got:

Spoiler (click to show/hide)

replace

Code: [Select]

void outputData();
with

Code: [Select]

void outputData(int,float,float,float,float,float,float);

replace

Code: [Select]

outputData(&quantity, &unitPrice, &subTotal, &discountAm, &subTaxable, &taxAm, &total);
with

Code: [Select]

outputData(quantity, unitPrice, subTotal, discountAm, subTaxable, taxAm, total);

replace

Code: [Select]

void calculate(float subTotal, int quantity, float unitPrice, float discountAm, float discountRate, float subTaxable, float taxAm, float total)
with

Code: [Select]

void calculate(float* subTotal, int* quantity, float* unitPrice, float* discountAm, float* discountRate, float* subTaxable, float* taxAm, float* total)

replace

Code: [Select]

subTotal    = quantity * unitPrice;
discountAm  = subTotal * discountRate / 100.0;
subTaxable  = subTotal - discountAm;
taxAm = subTaxable * TAX_RATE/ 100.00;
total = subTaxable + taxAm;
with

Code: [Select]

*subTotal    = *quantity * *unitPrice;
*discountAm  = *subTotal * *discountRate / 100.0;
*subTaxable  = *subTotal - *discountAm;
*taxAm = *subTaxable * TAX_RATE/ 100.00;
*total = *subTaxable + *taxAm;


Alternatively, this is the code I have after these changes:

Code: [Select]

#include <stdio.h>

#define TAX_RATE 8.50

//Function Declarations
void getData(int*, float*, float*);
void calculate(float*, int*, float*, float*, float*, float*, float*, float*);
void outputData(int,float,float,float,float,float,float);

int main (void)
{
// Local Declarations
int    quantity;

float  discountRate;
float  discountAm;
float  unitPrice;
float  subTotal;
float  subTaxable;
float  taxAm;
float  total;

// Statements
getData(&quantity, &unitPrice, &discountRate);
calculate(&subTotal, &quantity, &unitPrice, &discountAm, &discountRate, &subTaxable, &taxAm, &total);
outputData(quantity, unitPrice, subTotal, discountAm, subTaxable, taxAm, total);

return 0;
} // main

void getData(int *quantity, float *unitPrice, float *discountRate)
{
//Statements
printf("\nEnter number of items sold:         ");
scanf("%d", &*quantity);

printf("Enter the unit price:               ");
scanf("%f", &*unitPrice);

printf("Enter the discount rate (per cent): ");
scanf("%f", &*discountRate);

return;
}

void calculate(float* subTotal, int* quantity, float* unitPrice, float* discountAm, float* discountRate, float* subTaxable, float* taxAm, float* total)
{
//Calculations
*subTotal    = *quantity * *unitPrice;
*discountAm  = *subTotal * *discountRate / 100.0;
*subTaxable  = *subTotal - *discountAm;
*taxAm = *subTaxable * TAX_RATE/ 100.00;
*total = *subTaxable + *taxAm;

return;
}

void outputData(int quantity, float unitPrice, float subTotal, float discountAm, float subTaxable, float taxAm, float total)
{
//Statements
printf("\nQuantity sold:       %6d\n", quantity);
printf("Unit Price of items: %9.2f\n", unitPrice);
printf("                     ------------\n");

printf("Subtotal :           %9.2f\n", subTotal);
printf("Discount:           -%9.2f\n", discountAm);
printf("Discounted total:    %9.2f\n", subTaxable);
printf("Sales tax:          +%9.2f\n", taxAm);
printf("Total sale:          %9.2f\n", total);
}
Does that compile?

[Sirus]

It does 

Now I just need to figure out why and how this all works. Time for a textbook binge, I guess.