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Foundations of Software Engineering
Author:
Prof.Kevin AmaratungaProfessor
MIT Massachusetts Institute of Technology
USA
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2.1 Software development process Read Online
2.2 Requirements analysis Read Online
2.3 Software design Read Online
2.4 Software construction Read Online
2.5 Software testing Read Online
2.6 Software maintenance Read Online
2.7 Software configuration management Read Online
Virtually all countries now depend on complex computer-based systems. More and more products incorporate computers and controlling software in some form. The software in these systems represents a large and increasing proportion of the total system costs. Therefore, producing software in a cost-effective way is essential for the functioning of national and international economies.
Software engineering is an engineering discipline whose goal is the cost-effective development of software systems. Software is abstract and intangible. It is not constrained by materials, governed by physical laws or by manufacturing processes. In some ways, this simplifies software engineering as there are no physical limitations on the potential of software. In other ways, however, this lack of natural constraints means that software can easily become extremely complex and hence very difficult to understand.
Software engineering is still a relatively young discipline. The notion of ‘software engineering’ was first proposed in 1968 at a conference held to discuss what was then called the ‘software crisis’. This software crisis resulted directly from the introduction of powerful, third generation computer hardware. Their power made hitherto unrealisable computer applications a feasible proposition. The resulting software was orders of magnitude larger and more complex than previous software systems.
Early experience in building these systems showed that an informal approach to software development was not good enough. Major projects were sometimes years late. They cost much more than originally predicted, were unreliable, difficult to maintain and performed poorly. Software development was in crisis. Hardware costs were tumbling whilst software costs were rising rapidly. New techniques and methods were needed to control the complexity inherent in large software systems.
These techniques have become part of software engineering and are now widely although not universally used. However, there are still problems in producing complex software which meets user expectations, is delivered on time and to budget. Many software projects still have problems and this has led to some commentators (Pressman, 1997) suggesting that software engineering is in a state of chronic affliction.
As our ability to produce software has increased so too has the complexity of the software systems required. New technologies resulting from the convergence of computers and communication systems place new demands on software engineers. For this reason and because many companies do not apply software engineering techniques effectively, we still have problems. Things are not as bad as the doomsayers suggest but there is clearly room for improvement.
This class was also offered in Course 13 (Department of Ocean Engineering) as 13.470J. In 2005, ocean engineering subjects became part of Course 2 (Department of Mechanical Engineering), and the 13.470J designation was dropped in lieu of 2.159J.
Question: Which of the following cases of mixed expressions is/are correct (circle the correct one(s)), considering the following definition: double d; float f; int i; char c;
Choices:
’f’ - ’d’ is a double
f / 3.33 is a float
’f’ - ’d’ is an int
’f’ - ’d’ is a char
none of the above
Question: Considering the following definitions, which of the provided statements (if any) are invalid? double x= 0.5, y=4.9; double *px, *py, &rx=x;
Choices:
px =&x; double &rx = *px ;
px = py;
double &ry = rx;
px = px = rx;
px = py = *x;
Question: According to the following statement: const int *p;
Choices:
the value of the pointer p cannot change
the value of the integer that p points to cannot change
both pointer p and the value of the integer that p points tocannot change
both pointer p and the value of the integer that p points to can change
p is a constant pointer to int
Question: What is the result of the statement following the definitions given below? char c='b'; char *pc=&c; char *&rc=pc ; (*rc)++;
Choices:
it increases &rc
it stores 'b' in variable c
it increases *rc
it increases pc, by one byte
none of the above
Question: What will be the value of x after the execution of the following line? int x = (7>6 ? 1+8 : 8)
Choices:
6
7
1
8
9
Question: Which lines of the above code are assignments? Consider the following code:
Choices:
Statement a
Statement b
Statement c
Statement d
Statement e
Question: When the following logical test is true? ( x>=y && ! x && x* y < 0 && y==0)
Choices:
if x is greater than y, and y is equal to zero
if both x and y are equal to zero
if x is positive, and y is equal to zero
always
never
Question: Which line of the above code declares a variable without allocating memory for it? Consider the following code:
Choices:
Statement a
Statement b
Statement c
Statement d
Statement e
Question: Which line of the above code is both a definition and an initialization? Consider the following code:
Choices:
Statement a
Statement b
Statement c
Statement d
Statement e
Question: Considering the following definitions, which of the provided statements (if any), would give the value of x, assuming that x is a double that has been properly defined and initialized to a value? void *pp = &x; double *px=&x; double **ppx=&px;
Choices:
**ppx
*(static_cast <double*>(pp))
*pp
*(*(&px))
*( (double*)pp)
Question: Which of the following expressions give(s) as result an int equal to 6?
Choices:
’z’ - ’t’
13 % 7
7 % 2
29/5
55 % 7