Page 20 - DCAP102_DCAP_401_Foundations of Computer Programming

Unit 1: Foundation of Programming Languages

4. Diff cult to modify: It is difficult to correct or modify machine language programs. Notes
Checking machine instructions to locate errors is about as tedious as writing them initially.
Similarly, modifying a machine language program at a later date is so difficult that many

programmers would prefer to code the new logic afresh instead of incorporating the

necessary modifications in the old program.

In short, writing a program in machine language is so difficult and time consuming that it is
rarely used today.

Task Computer only understand 0 and 1 but we enter all values in the form of
alphabets how computer accept of understand these values.

1.7 Higher Level Languages

We have talked about programming languages as COBOL, FORTRAN and BASIC. They are
called high level programming languages. The program shown below is written in BASIC to
obtain the sum of two numbers.
LET X = 7
LET Y = 10

LET sum = X+Y
PRINT SUM
END
The time and cost of creating machine and assembly languages was quite high. And this was the
prime motivation for the development of high level languages.
Because of the difficulty of working with low-level languages, high-level languages were

developed to make it easier to write computer programs. High level programming languages
create computer programs using instructions that are much easier to understand than machine
or assembly language code because you can use words that more clearly describe the task being
performed.

Example: High-level languages include FORTRAN, COBOL, BASIC, PASCAL, C, C++
and JAVA.
1.8 Compiling High Level Language

Since a high level source program must be translated first into the form the machine can
understand, this is done by a software called Compiler which takes the source code as input and
produces as output the machine language code of the machine on which it is to be executed. This
is illustrated in fi gure.

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