How to perform typecasting in ALGOL?

Typecasting, or type conversion, is the process of changing an entity from one data type to another. This can be significant when you are trying to eliminate type compatibility issues without altering the underlying data.

ALGOL is a high-level computer programming language that was particularly influential in the development and design of later languages, such as Pascal, Java and C++. Performing typecasting in ALGOL is quite a straightforward process.

To begin the typecasting process, first, identify the variable you want to change its data type. For instance, you might have a real variable, but you need an integer for your computations. In the ALGOL language, the syntax for variable declaration is straightforward. Declare your variable as follows.

REAL variable1;
INTEGER variable2;

You've now declared your real and integer variables.

Next, assign a value to your real variable:

variable1 := 5.50;

This assigns the variable variable1 the value 5.50.

The final process is the typecasting itself. To assign the real value to the integer variable but in integer form, you would use the ALGOL ENTIER function:

variable2 := ENTIER variable1;

After the above operation, variable2 would possess the value 5. The ENTIER function essentially takes the integer part of a real number.

This is the basic way to perform an explicit type conversion in ALGOL. However, it's crucial to note that ALGOL also supports implicit type conversion, especially when dealing with numerical types. But opting for explicit type conversion is considered to be safer programming practice as it reduces bugs caused by unexpected data type changes.

It is also important to note that typecasting can result in data loss if not properly executed - for example, converting from a real to an integer, as in the example given, would end up with the fractional part being discarded. Hence, ensure that you are certain that typecasting is the most viable solution for your programming needs. If unsure, consider alternatives in order to ensure that your program is accurate and efficient.