C language standard leaves the exact definition of the behavior of several operations in the designer’s choice of compiler. These behaviors are defined by the implementation. This property allows the C compiler to use the instructions provided by the processor, so as to compile short and efficient executable programs directly. In return, it is sometimes the cause of portability of source code bugs in C.
Example; Take the entire division of a negative number: -5 / 3. While Fortran, Pascal and Ada specify a result of -1, Modula-3 specifies a result of -2 , C simply ensures that the absolute value of the remainder is strictly less than the absolute value as shown by a Computer Technician Sydney.
The only guarantee in this example is that the result will be between -2 and -1. For the programmer and the effectiveness of C, the most important is probably the fact that the sizes of the types of data shall comply only with the minimum guarantees. Thus, the int corresponding to the word machine can have a size of 16 bits on a 16 bit processor and a size of 64-bit on a 64 bit processor.
Syntactically valid constructs have completely undefined behavior during execution. In addition to the classic division by zero, we can report multiple variable assignment in the same expression: i = i + + / * undefined behavior . * /.
The syntax of C is designed to be short. Historically, it has often been compared to that of Pascal, an imperative language also created in the 1970s. Creating a program to display Hello World has since become the reference example to introduce the basics of a new language. The above terms are reserved to be exploited as keywords, and should not be used otherwise.
The C language includes many kinds of integers, with more or fewer bits. The size of the types is only partially standardized: the standard fixes only a minimum size and a minimum magnitude.
Minimum magnitudes are compatible with other binary representations of the two’s complement although this representation is almost always used in practice. This flexibility allows the language to be efficiently adapted to a wide variety of processors, but it complicates the portability of programs written in C by a Computer Technician Sydney.
Each signed integer may represent positive and negative numbers, and unsigned integers may not represent the natural numbers.