In C++ when you defined a variable and you want to print it you can just do
cout << "Your varibales is" << var1 << endl;
But why in c# you need a placeholder to do so?
Console.WriteLine("The answer is {0}" , answer);
Because i'm getting an error with printing the answer without the placeholder.
I have searched on the web, but it doesn't give the information i need..
It is not necessary you can do like this using concatenation subject to the condition that the variable must be a string , or else you have to use .ToString() for conversion and also to format the object:
Console.WriteLine("The answer is " + answer); // if answer is string
let answer be a DateTime object and you want to print the date only from that with the format "dd-MMM-yyyy" then you can use like this:
Console.WriteLine("The answer is " + answer.ToString("dd-MMM-yyyy")); // if answer is not string
Because this is the way how String.Format works. Console.WriteLine uses String.Format internally. You could write something like Console.WriteLine("The answer is " + answer); instead.
Placeholders are only used for string formatting: internally the WriteLine method will call the String.Format method, but you can either format it yourself, or use multiple Console.Write statements:
Console.Write("The answer is ");
Console.WriteLine(answer);
For instance is more or less equivalent to what you do in you C++ program since the statement:
cout << "Your varibales is" << var1 << endl;
basically boils down to:
cout2 = cout << "Your varibales is";
cout3 = cout2 << var1;
cout3 << endl;
and << on a cout is more or less equivalent to calling Write on the Console; the << simply returns the console object such that one can use chaining.
When you try
Console.WriteLine("The answer is " , answer); //without placeholder
This wont give you error but would not print the answer and the console output would be The answer is since you havent told where to put the variable answer in here. So if you want to print the answer you can use either concatenate using + as suggested by other post or you have to use placeholder
Letz take an example to understand where to use what. Let say you have many variables to show in the output. You can use placeholder so that it would be easy to read. Such as
string fname = "Mohit";
string lname = "Shrivastava";
string myAddr = "Some Place";
string Designation = "Some Desig";
Now letz say we wanted to show some string on the output which is like
Hey!!
Mohitwhose last name would beShrivastavais currently living atSome Placeand he is working asSome Desigwith so n so company.
Thus one of the way could be which is suggested by many of us.
Console.WriteLine("Hey!! " + fname + " whose last name would be " + lname + " is currently living at " + myAddr + " and he is working as " + Designation + " with so n so company.");
In this scenario Placeholder plays a vital role for better readability like
Console.WriteLine("Hey!! {0} whose last name would be {1} is currently living at {2} and he is working as {3} with so n so company.",fname,lname,myAddr,Designation);
With C#6.0 String Interpolation you can also do it in efficient way like
Console.WriteLine($"Hey!! {fname} whose last name would be {lname} is currently living at {myAddr} and he is working as {Designation} with so n so company.");
You can use string interpolation in addition to these other answers:
Console.WriteLine($"The answer is {answer}");
