unassigned use of variable

Yasmine Amin

Hi all was wondering if anyone can help me. I have an equation with an unknown variable (i'm using the equation to get its value) but i am unsure on how to use it. here is some of the code double acceptableProfit = callValidation.validatePrice(profitTxt.Text); //known double ebay1 = callValidation.validatePrice(ebayCostTxt.Text); //known double bprice = callValidation.validatePrice(boughtPriceTxt.Text); //known double recommendedSPrice; double ebay2 = recommendedSPrice/10; double payPal = (2.4 * recommendedSPrice + 20)/100; //to calculate the recommended sale price acceptableProfit = recommendedSPrice - (ebay1 + bprice + ebay2 + payPal); recommendedSPrice = acceptableProfit + ebay1 + bprice + ebay2 + payPal; but obivously for me to use the variable i must define a value for it

7 Replies

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Nilanka Dharmadasa17y ago
We can derive following equation to calculate recommendedSPrice.
double recommendedSPrice = (acceptableProfit + ebay1 + bprice - 20) / 87.6
Then using that value we can find the answers for following equations.
double ebay2 = recommendedSPrice/10;
double payPal = (2.4 * recommendedSPrice + 20)/100;
Yasmine Amin17y ago
thank for the replies again. Kirtan even though assigning expected sale price = 1 i still get the wrong answe. Jinge what i'm trying to do is develop a method where i advice the user on a sale price (roughly). The method is for ebay sales system where the user is charged an initail ebay fee (e1). an ebay sale fee = 10% of the sale price. a pappal fee which is 2.4% of sale price + 0.20. so what the method does is ask the use to enter the actual price of e1 (ebay initial fee), the buying price and how much profit would the user like to make. with these 3 figures i want to advice the user on a recommended sale price. here is an example:::: buying price = 10, e1 = 1, profit = 20 e2 = (10* recommended sale price) / 100 paypal = (2.4*recommended sale price)/100 + 0.20 so to calculate the recommended sale price profit recommended sale price - (buying price + e1 + e2 + paypal) ###note recommended sale price = y.... so in this example the solution is: 20 = y - (10 + 1 + (10y/100)+[(2.4y/100) + 0.20])-> 20 = y - (11 + Y/10 + [(2.4y + 20)/100])-> 20 = y - (11 + ((10Y + 2.4y + 20)/100))-> 20 = y - (11 + (12.4y + 20)/100)-> 20 = y - (1100 + 12.4y + 20)/100 -> 20 = y - (1120 + 12.4y)/100 -> 20 = [100y - (1120 + 12.4y)]/100 -> 2000 = 100y - 1120 - 12.4y -> 2000 + 1120 = 100y - 12.4y -> 3120 = 77.6 y -> y = 3120/77.6 -> y = 40. so what i have is an equation and i'm trying to solve it thanks again for u help
Kirtan Patel17y ago
I think you should initialize your recommendedSPrice=1 because you are using it in multiplication and division so initialize it as 1

use below code and

dont forget to mark "do you like this answer if it helped you :

//Assign Values 0 to Variable First
            double acceptableProfit = 0, ebay1 = 0, ebay2 = 0;
            double bprice = 0, recommendedSPrice = 1, payPal = 0;

            //use thee Variables
            acceptableProfit = callValidation.validatePrice(profitTxt.Text);
            ebay1 = callValidation.validatePrice(ebayCostTxt.Text);
            bprice = callValidation.validatePrice(boughtPriceTxt.Text);
            ebay2 = recommendedSPrice / 10;
            payPal = (2.4 * recommendedSPrice + 20) / 100;
            //to calculate the recommended sale price
            acceptableProfit = recommendedSPrice - (ebay1 + bprice + ebay2 + payPal);
            recommendedSPrice = acceptableProfit + ebay1 + bprice + ebay2 + payPal;
jinge17y ago
If the variable is not assigned, you can not use it as right operand. I think it makes sense to you. After seeing the three equations, I am not sure why the recommendSalePrice is not known. Let me know the detail if you want to get an answer.
Yasmine Amin17y ago
Thank you for ur reply but the problem is if i initialise the recommendSPrice then i ll get the wrong answer. What i have is 3 equation with 3 unknowns. The unknowns are ebay2, papypal and recommended sale price and the equations are
ebay2 = recommendedSalePrice/10 payPal = [2.4 * recommendedSalePrice + 20] Profit = recommendedSalePrice - (ebay1 + bPrice + ebay2 + paypal). i can solve the equation on paper i just dont know how write it in code..

jinge17y ago

     double acceptableProfit = callValidation.validatePrice(profitTxt.Text); 
            //known 
            double ebay1 = callValidation.validatePrice(ebayCostTxt.Text); //known
            double bprice = callValidation.validatePrice(boughtPriceTxt.Text); 
            //known 
            double recommendedSPrice;
            recommendedSPrice = acceptableProfit + ebay1 + bprice + ebay2 + payPal;
            double ebay2 = recommendedSPrice/10; 
            double payPal = (2.4 * recommendedSPrice + 20)/100; //to calculate the recommended sale price 
            acceptableProfit = recommendedSPrice - (ebay1 + bprice + ebay2 + payPal);

recommendedSPrice should give a value before using it.

Kirtan Patel17y ago
Friend,

its better to initialize variable before using it :-)

see below corrected code :-)

dont forget to mark "do you like this answer" if my answer helped you :)

             //Assign Values 0 to Variable First
            double acceptableProfit = 0, ebay1 = 0, ebay2 = 0;
            double bprice = 0, recommendedSPrice = 0, payPal = 0;

            //use thee Variables
            acceptableProfit = callValidation.validatePrice(profitTxt.Text);
            ebay1 = callValidation.validatePrice(ebayCostTxt.Text);
            bprice = callValidation.validatePrice(boughtPriceTxt.Text);
            ebay2 = recommendedSPrice / 10;
            payPal = (2.4 * recommendedSPrice + 20) / 100;
            //to calculate the recommended sale price
            acceptableProfit = recommendedSPrice - (ebay1 + bprice + ebay2 + payPal);
            recommendedSPrice = acceptableProfit + ebay1 + bprice + ebay2 + payPal;