Q2)Explain different phases used in system development

Explain different phases used in system development
ans:-
Th steps of SDLC are shown below.

Let's know about them in brief.

1)Problem definition:-The first step is problem definition(study). The intent is to identify the problem, determine its cause, and outline a strategy for solving it. It defines what ,when who and how project will be carried out.

2) System analysis:-

Once the problems identified, it is time to analyze the type of software that could answer the problems encountered. System analysis (may be by system analyst) will take a look at possible software. The goal of a system analysis is to know the properties and functions of software that would answer the concerns solicited from intended users.

Step 3.

   Systems Design: In this phase we start design of proposed new system.It describes desired features and operations in detail, including screen layouts, business rules, process diagrams, pseudo code and other documentation.

.step 4 System Development:-

System development (Coding):

After designing the new system, the whole system is required to be converted into computer understanding language. Coding the new system into computer programming language does this. It is an important stage where the defined procedure are transformed into control specifications by the help of a computer language.

step 5. Testing:-

                           Before actually implementing the new system into operations, a test run of the system is done removing all the bugs, if any. It is an important phase of a successful system. After codifying the whole programs of the system, a test plan should be developed and run on a given set of test data. The output of the test run should match the expected results.

step 6 Implementation

After having the user acceptance of the new system developed, the implementation phase begins. Implementation is the stage of a project during which theory is turned into practice. During this phase, all the programs of the system are loaded onto the user's computer. After loading the system, training of the users starts. Main topics of such type of training are:

• How to execute the package
• How to enter the data
• How to process the data (processing details)
• How to take out the reports

step 7 System Evaluation:-
Management should conduct post-implementation reviews at the end of a project to validate the completion of project objectives and assess project management activities. Management should interview all personnel actively involved in the operational use of a product and document and address any identified problems.

8. System Maintenance:-

Maintenance is necessary to eliminate errors in the system during its working life and to tune the system to any variations in its working environment. It has been seen that there are always some errors found in the system that must be noted and corrected. It also means the review of the system from time to time. The review of the system is done for:

• knowing the full capabilities of the system
• knowing the required changes or the additional requirements
• studying the performance

What is feasibility study? Explain its types.

Q)What is feasibility study? Explain its types.

Ans:
Feasibility study:-
                       It is the measure and the study of how beneficial the development of the system would be to the organization. This is known as feasibility study. The aim of the feasibility study is to understand the problem and to determine whether it is worth proceeding.
It has following types.

1.Technical feasibility: - This is concerned with availability of hardware and software required for the development of system.The issues with can be like:

1.1) Is the proposed technology proven and practical?

1.2)the next question is: does the firm possess the necessary technology it needs. Here we have to ensure that the required technology is practical and available. Now, does it have required hardware and software?

1.3)The Last issue is related to availability of technical expertise. In this case, software and hardware are available but it may be difficult to find skilled manpower.

2.Operational feasibility:- It is all about problems that may arise during operations. There are two aspects related with this issue:

2.1) what is the probability that the solution developed may not be put to use or may not work?

                                   2.1) what is the inclination of management and end users towards solutions?

Besides these all some more issues;

                                                           a) Information: saying to provide adequate, timely, accurate and useful information to all categories of users.

                                                       b) Response time, it says about response about output in very fast time to users.

                                            c) Accuracy: A software system must operate accurately. It means, it should provide value to its users. It says degree of software performance.

           d) Services:- The system should be able to provide reliable services.

             e)Security:- there should be adequate security to information and data from frauds.

f) Efficiency: The system needs to be able to provide desirable services to users.

3) Economic feasibility: - It is the measure of cost effectiveness of the project. The economic feasibility is nothing but judging whether the possible benefit of solving the problem is worthwhile or not. Under "cost benefit analysis", there are mainly two types of costs namely, cost of human resources and cost of training.

                                                             The first one says about salaries of system analysts, software engineers, programmers, data entry operators etc. whereas 2nd one says about training to be given to new staffs about how to operate a newly arrived system.

4) Legal feasibility: - It is the study about issues arising out the need to the development of the system. The possible consideration might include copyright law, labor law, antitrust legislation, foreign trade etc.

Apart from these all we have some more types:

behaviour feasibility, schedule feasibility study etc.

NEB41:Explain datatypes used in “C”.

Q41)Explain datatypes used in “C”.

ans:-
 Data type:- 
  When we write program we use different variable. Before we use them in our program we declare them with their data format to be used in memory. This format is called 'data type'.
                              Following are the types.There are two types of data types.

                         a) Basic data type (Primary data type)

                         b) Derived data type(Secondary data type) mostly called "Qualifier"

                                          

  Let's have look in detail about primary data types.

                                a) Basic data type:- Under this category we have four types. They are int,float,char and double.Let's know about them.

                                                a.1) int:- 

                                                                It's a basic data type; we can use only integer type of value by declaring variable with this. e.g

                                                                                                int sum; 

                                                                           This declaration declares sum as integer type of variable. We can  use or input only integer type of value and under some range. We can not use other values like fractional or exponential. And if we used then, the computer truncates the fractional part. eg. int sum=3.4; 

                                                                                        Here, we used int data type but assigned fractional value (3.4); So computer stores only 3 instead of 3.4. It occupies 2 bytes in memory and working range is -32768 to +32767.

                                                a.2) float:-

                                                                    Suppose, we want to use fractional numbers; then we use float data type. This type supports numbers with decimal digits(after dot) for a variable. Unlike integer (int ), it does not truncate the fractional part and whole part is stored in memory. 

                                                                        float pi=4.67;

                                                                        float a=6;

                                                                         We have taken simple examples. In first. the computer stores 4.67 in memory. Where as in second we can see that number is integer but it has been declared as float, in this case computer automatically converts the integer into float by putting dot and zeros. i.e computer takes 6.00. In memory computer occupies 4 bytes for this and can store up to or in range 3.4e-38 to 3.4e+38;good range it has to work with.

                                                a.3) Char:-

                                                                         Char stands for a single character or sequence of many characters. We use this data type if we want to use one character or  a set (called string) to be inputted. To be clear, let's have an example,

                                                                                    syntax goes like,

                                                                                   data type variable/s;

                                                                                   char a,b;

                                                                    here, a and b are character type of variables and can store one character. If we want to store one character as a constant then we can assign like,

                                                                         char a='n';

                                                                          here, a is character type of variable and is storing 'n';

                                                                                                                                                                         But if we want to store more than one character or input then we can use,

                                                                      char a[10];

                                                                                                        here, we can enter a string having maximum ten characters;we can also enter just one character. This concept is called arrayed characters. In the case of constant,we use

                                                                    char a[10]="text"; 

                                                                    String "text" is stored in variable 'a' and it can store maximum 10 characters.

                                                        

                                                    a.4) Double:-  

                                                                             This data type is used  for exponential values and for more accuracy of digits.It's working range is more than others. so if we want to use long numbers of any type and high accuracy then...? for example,

                                                                                                            data type variable;

                                                                                                             double ab;

                                                                                                  'ab' is a variable of double type. It can store exponential values (3x104). It ca n be written as 3e+4 or 3E+4. If power is in negative form then it can be in 3e-4 or 3E-4. It has one advantage over others that it can be used in place of others easily.

neb40:Explain about operator and its types.

ans:
operator:- It is a symbol or a character used in programming. It is used to carry out some operation.
for example: +,-,= etc
It is of following types.
1)Arithmetic operator: It is used to do arithmetic calculations/operation.
 It has following types.

 +         -----------> used for addition.example is a+b. It means we are performing addition with the help of operand a and b
-           ------------>It is used for subtraction.Example is a-b.  It means we are performing subtraction with the help of operand a and b
* -------------------->used for multiplication.example is a*b. It means we are performing multiplication with the help of operand a and b
/---------------->used for division.example is a/b. It means we are performing division with the help of operand a and b

%---------------->used for remainder division.example is a%b. It means we are performing division with the help of operand a and b.It gives us remainder after division.

2)relational operator: 

This operator is used to perform comparisons between variables.It supports us to take decision logically. example,x>y ,x>=y etc

Relational operator has following types.

>------> It is used to show greater than. like x>y

>=----->It is used to show greater than or equals to.like x>=y

<-------->It is used to show a variable is smaller than another.like x<y

<=-------> It is used to show smaller than or equals to with another variable.Like x<=y

!=----------> I simply says , two variables are not equal in value.like x!=y

==---------->It says two variables have same value.It is used to test values of two variables.

3)Logical operator:-

                                   This operator is quite helpful when we want to combine multiple  conditions and take decision.It returns values in the form of 0 o 1.It works logically.

Its types are:

3.a)and (&&)-----------> It is called 'and'operator.It is used to combine multiple conditions.It gives us true output if all of them are true otherwise we get false output.

 example:if(a>b && a>c)

                      {

                            display a     

                        }

 we can see here that to be greatest,value of 'a' must be greater than b and c. So we use here '&&'

   

  3.b)or(||):- It is called 'or'operator.It is used to combine multiple conditions.It gives us true output if anyone of them is true or all are true otherwise we get false output.

 example:if(a==90 || b==90 || c==90)

                      {

                            display right angle triangle  

                        }

 we can see here that to be right angled triangle,either 'a'or 'b'or 'c' a must be 90 . So we use here '||'.

3.c) !(not )operator:-

                                It is used to reverse the result.
example
int a=5;
if(!(a==5))
{
printf("it is\n");
}
else
{
printf("it is not\n");
}
here ,the value is 5 but we get output "it is not".It is called reversing the output.

4) Assignment operator:
                                an operator ,symbolized by '=' character,is called assignment operator.It assigns value to variable.
example:
int a=6;
It means, we are assignming value 6 to variable a.

5)Unary operator:- this operator  works on one operand only.It has two types.
                               I) increment operator:- It increases the value of given variable by one.For example: ++y or y++
                                             It can be classified into pre-increment and post increment.
                                                 pre-increment:- It is written as ++x.It means first increase the value and then use that.
                                                 post-increment: It is written as x++.It means, first use that and then increase its value by one.

                               II)decrement operator:- It decreases the value of given variable by one.For example: --y or y--
                                             It can be classified into pre-decrement and post decrement.
                                                 pre-decrement:- It is written as --x.It means first decrease the value and then use that.
                                                 post-decrement: It is written as x--.It means, first use that and then decrease its value by one.

Besides these all, we have some other operators .like  bitwise,

neb42:WAP to show use of command “remove” and “rename” in data file handling with the help of example.

ans:

remove:this function is used to delete data file from the system.

syntax is:

remove("filename");

we have following example as a program.

//WAP to show use of command “remove” in data file handling with the help of example.

 #include<stdio.h>

#include<conio.h>

void main()

{

char choice;

printf("enter ur choice\n");

choice=getchar();

if(chice=='y')

        {

              remove("data.txt");

            printf("data file deleted sccessfully\n");

         }

else

{

printf("sorry, data filenot found\n");

}

getch();

}

rename: it is used to rename the file.

syntax is

rename("old name","new name");

 example is given below.

//WAP to show use of command “rename” in data file handling with the help of example.

 #include<stdio.h>

#include<conio.h>

void main()

{

char choice;

printf("enter ur choice\n");

choice=getchar();

if(chice=='y')

        {

              rename("data.txt","data1.txt");

            printf("data file renaming done successfully\n");

         }

else

{

printf("sorry, data file not found\n");

}

getch();

}

neb38:WAP to count total number of students having age in range 20 and 40 out of ‘n’ number of students.

//WAP to count total number of students having age in range 20 and 40 out of ‘n’ number of students
#include<stdio.h>
#include<conio.h>
void main()
{
int n,i,count=0;
in age[1000];
printf("enter total students' number-below 1000\n");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("enter age\n");
scanf("%d",&age[i]);
   if(age[i]>=20 && age[i]<=40)
              {
                count++;
              }
 }
printf("total students=%d\n",count);
getch();
}

neb39:Differentiate between break and continue with example

Differentiate between break and continue with example
ans:
differences are :

	break	continue
1	It terminates the execution.	It takes the iteration to next level(skipping).
2	It can be used in loop and switch.	It can be used in switch
3	It uses keyword ‘break’.	It uses keyword ‘continue’.
4	Its syntax is break;	Its syntax is continue;
5	Example is For(i=1;i<=4;i++) {   If(i<=2)     Printf(“%d\n”,i);      Break; } }	Example is For(i=1;i<=4;i++) {   If(i<=2)     Printf(“%d\n”,i);      continue; } }
	output is:1	output is:1,2