These two are the universal data structure supported by approx all programming languages. So data exchange between one language to another is easy by JSON.
JSON string example is as below
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{
"squadName":"Super hero squad",
"homeTown":"Metro City",
"formed":2016,
"secretBase":"Super tower",
"active":true,
"members":[
{
"name":"Molecule Man",
"age":29,
"secretIdentity":"Dan Jukes",
"powers":[
"Radiation resistance",
"Turning tiny",
"Radiation blast"
]
},
{
"name":"Madame Uppercut",
"age":39,
"secretIdentity":"Jane Wilson",
"powers":[
"Million tonne punch",
"Damage resistance",
"Superhuman reflexes"
]
},
{
"name":"Eternal Flame",
"age":1000000,
"secretIdentity":"Unknown",
"powers":[
"Immortality",
"Heat Immunity",
"Inferno",
"Teleportation",
"Interdimensional travel"
]
}
]
}
Why use JSON?
As JSON format is text only, it can be sent
to server and also can received from a server, and also can be used as a data
format by any programming language.
If you receive data from a server, in JSON
format, you can use it like any other JS object.
JSON Syntax
JSON syntax is derived from JS object
notation syntax.
• Data
is in name/value pairs
• Curly
braces hold objects
• Data
is separated by commas
• Square
brackets hold arrays
JSON Data
JSON data is written as name or value pairs.
A name or value pair consists of a field name like this “”, and it will follow by a colon, and also followed by a value:
Example
{“name”:”Ayan” }
JSON – Evaluates to JS Objects
The JSON format is a also JavaScript objects.
In JSON, keys must be strings, written with
double quotes:
JSON
{ “name”:”Ayan” }
In JSON, keys can be strings, numbers, or
identifier names,
{ name:”Ayan” }
JSON with JavaScript Syntax
JSON syntax is derived from JavaScript object
notation, very little extra software is needed to work with JSON within JS.
With JS you can create an object and assign data to it.
Example
Access a JavaScript object
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<!DOCTYPE html>
<html>
<body>
<pid="mydemo"></p>
<script>
varmyObj,x;
myObj={name:"Ayan",age:25,city:"Mumbai"};
x=myObj.name;
document.getElementById("mydemo").innerHTML=x;
</script>
</body>
</html>
Result
Ayan
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<!DOCTYPE html>
<html>
<body>
<pid="mydemo"></p>
<script>
varmyObj,x;
myObj={name:"Ayan",age:25,city:"Mumbai"};
x=myObj["name"];
document.getElementById("mydemo").innerHTML=x;
</script>
</body>
</html>
produce the same output as above
JSON Values
In JSON, values must be one of the following data types:
a string
a number
an object
an array
or one of the following literal names
false
true
null
Fig : JSON Value
JSON String Value
String value is represented in quotation any unicode character is used to create string.
like
” ” //empty string “Ram” //string value “\”” // use of escape character “\uXXXX” // unicode value
JSON Numbers
JSON allows numbers as an integer or a floating point numbers.
Example
25 24.25 3.55 3.1e3
JSON Objects
Values in JSON can be objects. It contains zero or more name value pairs in curly braces seperated by comma
JSON Array are surrounded by [ (squrae bracket) and zero or more values or elements are seperated by comma.
The values in array may be of different types.
Example
[“red’,”blue”,”green”, “orange”]
A composite JSON structure is also possible
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[
{
"name":"Ayan Das",
"age":25,
"knowledge":["typing","SEO"]
},
{
"name":"RamBag",
"age":39,
"knowledge":["Coding","Web designing"]
}
]
Here a JSON array contains two objects and each object contains string, number and array values
JSON is purely a data format — it contains
only properties, no methods.
JSON need a double quotes to be used around strings and property names. Single quotes are not valid in a JSON.
A single misplaced colon or comma can cause a JSON file to go wrong, and not working that JSON file. Always be careful to validate any data in JSON. A validate JSON using an application like JSONLint.
JSON can be taken the form of any data type that is valid for inside JSON, not just arrays or objects. So, a single string or a number can be a valid JSON object.
Unlike in JavaScript code in which object properties may be unquoted, in JSON, only quoted strings may be used as properties.
Converting between objects and textSection
In JSON can be set the XHR request to convert
the JSON response directly into a JS object using:
request.responseType = ‘json’;
But sometimes can be receive a raw JSON string, and need to convert it to an object.
when try to send a JavaScript object across the network, then need to convert it to JSON (a string) before sending.
These two problems are so common that a built-in JSON object is available, which contains the following two methods:
parse(): Accepts a JSON string as a parameter, and returns the corresponding JavaScript object.
stringify(): Accepts an object as a parameter, and returns the equivalent JSON string form.
console.table(obj); prints array in tabular format console.log(obj[0].name); print first objects name for (var row in obj) will iterate each object and access its properties in name value pair
Angularjs provides way to bind HTML select element with angularjs model
select directive also provide dynamic option value using ng-repeat and ng-options
When the item from select element is get selected from option then it is bind with the value of ng-model associated with select element using angularjs two way binding.
Setting option value using value attribute of option element will set this value as string.
On selection this value in ng-model the model variable must be string type.
There are different kinds of overlays for modal dialogs for prompting,
overlays for info or warning boxes, tabbed overlays, alerting usersoverlays for displaying complex data.
The overlay can implement on HTML like
images, links, forms, tables, any type of div and any can be styled with CSS,
like rounded borders, shadows or gradients etc.
Core behaviors are configurable
such as positioning, animation durations and closing the overlay.
Overlay offers a good container for other tools. Think of scrollables, tabs or accordions inside the Overlay.
“switch” statement takes a value as a expression for
equality testing against a list of values/case.
syntax for a switch statement:-
C
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switch(expression){
caseconstant-expression:
statement(s);
break;/* optional */
caseconstant-expression:
statement(s);
break;/* optional */
/* you can have any number of case statements */
default:
/* Optional */
statement(s);
}
Rules of switch statement −
In a “switch” statement we can have any number of
case.
for equality testing against a list of
values/case, constant-expression for a case must be the same data type
as the variable in the switch expression.
When “switch” expression value is equal to a
case, the statements following that case will execute until a break statement is reached/executes.
When a break statement is reached/executes, the
switch statement terminates, and the control jumps to the outside of switch.
a break
is a optional. If there is no break
in the switch case, the flow of control will jump to the next case of
switch until a break is reached.
A switch statement also have a default case, which appear at the end of the switch. when none of the cases is true then default case will execute.
No break is needed in the default case. “default” case is also an optional.
Example: Write a program to take one numbers from user between 1 to 3. Write entered number in words if number between 1 to 3 otherwise print wrong number using switch.
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#
include<stdio.h>
intmain(){
intn;
printf(" enter number between 1 to 3");
scanf("%d",&n);
switch(n){
case1:
printf("\n one");
break;
case2:
printf("\n two");
break;
case3:
printf("\n three");
break;
default:
printf("\n wrong number");
}
return0;
}
OUTPUT
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enter number between1to3
2// user entered 2
two
Note: In the above program, for example user enters a number 6 then output will be as follows:
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3
enter number between1to3
6// user entered 6
wrong number
Example: Write a program using switch statement but without break.
C
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#include <stdio.h>
intmain(){
charc='B';
switch(c){
case'A':
printf("Excellent!\n");
break;
case'B':
case'C':
printf("Well done\n");
case'D':
printf("You passed\n");
break;
case'F':
printf("Better try again\n");
break;
default:
printf("Invalid Character \n");
}
return0;
}
OUTPUT
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Well done
You passed
Description: Because if there is no break in the switch case, the
flow of control will jump to the next case of switch until a break is reached.
Note: In the above program, for example value of char variable c = ‘ A’ then the output will be as follows:
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Excellent
Nested switch
statements
In C programming language we can define switch
statement within another switch.
In
the C language decision making statement is executes if the given condition is
true otherwise conditional block will never execute.
In C language non-zero and non-null values are consider as true, and zero or null values are consider false.
if statement
Syntax of an if statement −
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if(expression)
{
statements;
}
In a if statement if the expression result is non zero true, then the block of statement of the ‘if’ statement will be executed. If the expression result is zero, then the block of statement of the ‘if’ statement will not executed and control sent to the next line of if block.
Example: Write a program to demonstrate the ‘if’ statement.
C
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#include <stdio.h>
intmain()
{
intx=10;
inty=25;
if(x<y)// condition x<y is true it returns 1 therefore if block will execute
{
printf("Sum of x+y = %i",(x+y));
}
printf("\n after if statement %d",z);
return0;
}
OUTPUT
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Sum ofx+y=35
after ifstatement
In the above program if(x>y) then the condition will be false and ‘if’ block will never execute.
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#include < stdio.h ><br> int main() {<br> int x = 10;<br> int y = 25;<br> if (x > y) // condition x>y is false therefore if block will not execute <br> {<br> printf("Sum of x+y = %i", (x + y));<br> }<br> printf("\n after if statement");<br> return 0;<br> }<br>
OUTPUT
1
after ifstatement
if-else statement
Syntax of an ‘if-else’ statement −
C
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if(expression)
{
statements
}
else
{
statements
}
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Ina‘if-else’statement ifthe expression is <strong>non zero,</strong>thenthe block of statements of the'if'statement will be executed.Ifthe statement expression is <strong>zero,</strong>thenthe block of code of the'else'statement will executed.<br><br>
Example: Write a program to take two numbers from user and find the grater between them using ‘if-else’ statement.
C
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#include <stdio.h>
intmain()
{
intx;
inty;
printf("enter 1st number");
scanf("%d",&x);// 10
printf("enter 2 nd number");
scanf("%d",&y);// 30
if(x>y)// check condition x>y
{
printf("grater value= %d",x);
}else{
printf("\n grater value= %d",y);
}
return0;
}
OUTPUT
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enter1stnumber34
enter2nd number2
grater value=34
Nested If else
In a C language we can use if statement inside another if statement(s).
Syntax of an ‘nested -if’ statement −
C
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if(expression1){
statements
If(expression2)
{
statements
}
}
Example: Write a program to take two numbers from user if both number are between 1 to 9 then print “Good” using nested-if statement.
C
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#
include<stdio.h>
intmain(){
intx;
inty;
printf("enter 1st number");
scanf("%d",&x);// 5
printf("enter 2nd number");
scanf("%d",&y);// 7
if(x<10)// check condition x<10
{
if(y<10)// nested-if, check condition y<10
{
printf("Good");
}
}
return0;
}
OUTPUT
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enter1stnumber3
enter2ndnumber2
Good
Nested if else statement
In a C language we
can use if or if-else statement inside another if or if-else statement(s).
Syntax of an ‘if-else’ statement −
C
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if(expression1)
{
statements
if(expression2)
{
statements
}
}
else
{
if(expression3)
{statements
}
}
Example: Write a program to take three numbers from user and find the grater among them using ‘nested if-else’ statement.
