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Percentage calculation always returns me 0 [duplicate]

This question already has answers here:
Why do these division equations result in zero?
(10 answers)
Why does integer division in C# return an integer and not a float?
(8 answers)
Closed 4 years ago.
I'm calculating the percentage to add in a datagrid, but when I report the data it always returns me 0, what am I doing wrong?
if I have the following case: the variable quantidadeInstalada has the value of 10 and the goal has 20 the concluido would have to return me 50 but it returns me 0
private void AdicionarPessoa()
{
string Valida = ValidaPessoa();
if (Valida.Equals(""))
{
double concluido=0, falta=0;
int quantidadeInstalada = Convert.ToInt32(ttbQuantidade.Text);
int meta = Convert.ToInt32(ttbMetaPessoa.Text);
concluido = (quantidadeInstalada/meta)*100;
falta = 100-concluido;
MessageBox.Show(concluido.Text);
}
else
MessageBox.Show(Valida);
}

It's probably due to the precision of the int. Use a decimal or double instead.
When we use an integer, we lose precision.
Console.WriteLine(100 / 17); // 5
Console.WriteLine(100 / 17m); // 5.8823529411764705882352941176
Console.WriteLine(100 / 17d); // 5.88235294117647
Console.WriteLine(100 / 17f); // 5.882353
Since integers always round down, 0.99 as an integer is 0.
Note that for precision, the types of the inputs matters.
double output = input1 * input2;
For example:
double outputA = 9 / 10;
Console.WriteLine(outputA); // 0
double outputB = 9 / 10d;
Console.WriteLine(outputB); // 0.9
double outputC = 9d / 10;
Console.WriteLine(outputC); // 0.9
Here is a Fiddle.

It's because you're doing integer division. You can fix it by casting one of the variables to a double like this:
concluido = ((double)quantidadeInstalada/meta)*100;

When you're dividing int by int (as in "quantidadeInstalada/meta"), you'll get an int. Either use a fractional type (e.g. decimal, double) from the very beginning, as Shaun suggested, or (if the integral types have to stay), cast the values to a fractional type in the division expression (as itsme86 shown).

math operations always returns 0 c# [duplicate]

This question already has answers here:
C# is rounding down divisions by itself
(10 answers)
C# double not working as expected [duplicate]
(1 answer)
Closed 7 years ago.
I have c# program that calculates percentage and returns int value, but it always returns 0.
I have been writing code for 16 constitutive hours so I appreciate if you find the mistakes within it.
I debugged my code and I found that the value is being passed correctly.
private int returnFlag(int carCapacity, int subscribers)
{
int percentage = (subscribers / carCapacity)*100;
return percentage;
}

What you're seeing is the result of operating on two integers, and losing the fractional portion.
This piece of code, when using the values 5 and 14, will truncate to 0:
(subscribers / carCapacity)
You need to cast one of the operands to a double or decimal:
private int returnFlag(int carCapacity, int subscribers)
{
decimal percentage = ((decimal)subscribers / carCapacity) * 100;
return (int)percentage;
}

The issue is that since you're performing math on int (read: integer) values, any fractions or remainders get thrown out. This can be seen by changing your code to
int percentage = (subscribers / carCapacity);
percentage *= 100;
Since (subscribers / carCapacity) results in less than one, the only possible number an int can hold is 0 - and 0 * 100 is 0.
You can fix this by converting to a more precise number, such as double, before performing operations:
private int returnFlag(int carCapacity, int subscribers)
{
double percentage = ((double)subscribers / (double)carCapacity) * 100.0;
return (int)percentage;
}

Integer types (int) don't work with fractions. Change the types you are working with in your division to decimal, double, single, or float.

Simple calculator always return 0

In my C# application I want to implement a simple calculation. I got this code:
private void button1_Click(object sender, EventArgs e)
{
int percentField;
int priceField;
int result;
percentField = int.Parse(txtPercentNew.Text);
priceField = int.Parse(txtPriceNew.Text);
result = priceField / 100 * percentField;
MessageBox.Show(result.ToString());
}
But the problem is the MessageBox displays me 0. I can't figure out why.
Can someone please give me a hint what I am doing wrong?

Your variables are integers, which means that / performs integer division. Unless priceField is at least equal to 100 you will always get 0 as the result.
You can correct the problem by casting priceField to a floating point type before dividing:
(double)priceField / 100 * percentField;
However, this will not work while result is of type int because the compiler wants to protect you from inadvertent rounding errors. So you either have to cast back to an integer (losing precision due to rounding):
result = (int)((double)priceField / 100 * percentField);
or else make result be a double as well.

You are using integers instead of floating point numbers.
As a consequence, rounding off occurs during calculation.
Use float or double instead of int.

Probably your priceField is less then 100 and since you doing integer division, it creates 0 as a result.
From / Operator (C# Reference)
When you divide two integers, the result is always an integer. For
example, the result of 7 / 3 is 2. To determine the remainder of 7 /
3, use the remainder operator (%). To obtain a quotient as a rational
number or fraction, give the dividend or divisor type float or type
double. You can assign the type implicitly if you express the dividend
or divisor as a decimal by putting a digit to the right side of the
decimal point, as the following example shows.
Just cast one of your variables to floating point type like;
result = priceField / 100d * percentField;
or
result = (double)priceField / 100 * percentField;

You are working with only integers, try
double result;
result = priceField / (double)100 * percentField;
In your code, you are dividing by 100. Which means every int you are going to divide less than 100 will result in a value between [0 - 1]. When implicitly casting to an int, the result will be floored. Therefor, a 0.1 will become 0 - a 0.9 will become 0 - ...

try cast to double, because you're working with integers it results in 0.
example here

The problem is you're using int for each value.
Change result to a double and try this:
result = (double)priceField / 100 * percentField;
It should work; however, if you want to do this properly I recommend you read about MidpointRounding.

C# Calculations With Decimal Places

I am having trouble with basic multiplication and division in C#.
It returns 0 for ((150 / 336) * 460) but the answer should be 205.357142857.
I presume this is because (150/336) is a fractional number, and C# rounds this down to 0.
How do I correctly calculate this taking into consideration all decimal places?

No, it is because 150/336 is an integer division which always truncates the decimal part since the result will also be an int.
So one of both must be a decimal number:
double d = 150d / 336;
See: 7.7.2 Division operator
The division rounds the result towards zero, and the absolute value of
the result is the largest possible integer that is less than the
absolute value of the quotient of the two operands. The result is zero
or positive when the two operands have the same sign and zero or
negative when the two operands have opposite signs.

((150 / 336) * 460)
Those numbers are integers, they have no decimal places. Since 150 / 336 evaluates to 0 in integer math, multiplying it by anything will also result in 0.
You need to explicitly make each number a double. Something like this:
((150d / 336d) * 460d)

You are doing integer arithmetic not floating/double. To specify a floating point double constant use the 'd' suffix.
double d = (150d / 336d) * 460d;

150/336 gives you an int as result, thus 0. you need to the division so it you'll have a double as result
(((double)150 / 336) * 460)

If you're using variables then you should write it down like this:
double d = ((double)firstNumber/ secondNumber) * thirdNumber;
For more information: https://www.dotnetperls.com/divide

Dividing by a higher number returning 0

When I try to do this
double test = ((2 / 7) * 100);
it returns 0.
Does anybody know why this is and how to work around it?
Thanks

2 / 7 is integer division, and will return 0. Try this instead
2.0 / 7
(double) 2 / 7

You're dividing integers.
If you want a non-integer result, at least one operand must be a float or double (or decimal).
You can do that by adding .00 to any of the literals to create a literal.

You are dividing integers, so 2 / 7 becomes already 0. Just try 2.0 / 7.0 and you'll get the correct result.

It's doing integer division because all the operands are integers.
To fix it, change at least one the operands to doubles like this:
double test = ((2.0 / 7.0) * 100.0);

You are doing integer math, and only converting to double when you have the final result.
2 / 7 = 0
while
2.0 / 7.0 = 0.285714285714285
Do the math with double values:
double test = ((2.0 / 7.0) * 100.0);

It's because of division. A division of two int numbers returns int number truncating any decimal points. Hence the result of the operation 2/7 will be 0.
It should be something like this:
double test = ((2.0 / 7.0) * 100.0);