Differentiate between 'out' and 'param' keywords in c# with example.
| out keyword | params keyword |
| It is not necessary to initialize parameters before pass data at the function call. | It is not necessary to initialize parameters before they pass out we can pass multiple values using this keyword. |
| It is necessary to initialize the value of a parameter before returning the value to the calling method. | It is not necessary to initialize the value of a parameter before returning to the calling method, only accessed. |
| The declaring of parameters through 'out' parameters is useful when a method returns multiple values. | it returns a single value. |
| When out keyword is used the data only passed in unidirectional. | When the params keyword is used the data is accessed only. |
Example
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ThreadDemo
{
class OutAndParamsDemo
{
private int CountDigit(long value)
{
int count = 0;
while (value != 0)
{
value /= 10;
count++;
}
return count;
}
public void PrintNumberOfDigits(params long[] num)
{
foreach (long item in num)
{
Console.WriteLine($'{item} has {this.CountDigit(item)} digits.');
}
}
public void GetValueByFunction(out int x, out int y)
{
x = 0;y = 0;
x = 100;
}
public static void Main(string[] args)
{
OutAndParamsDemo outAnd = new OutAndParamsDemo();
int n, p;
// call the print number of digits function
outAnd.PrintNumberOfDigits(751, 125, 485, 452196, 4152, 1450, 10101010101);
// call the get value by function
outAnd.GetValueByFunction(out n, out p);
Console.WriteLine($'N : {n} P : {p}');
}
}
}
Output
