# Constants in Hindi

#### Constants

• Constant की value fixed होती है |
• Constant किसी भी data type का हो सकता है |
• Constant को Literals भी कहते है |
• Constant Pointer भी होता है |

##### Syntax :
const data_type variable_name = value (optional) ;

#### Types of Constant :

• Integer Constant
• Decimal Constant
• Octal Constant
• Floating-point / Real Constant
• Character Constant
• String Constant
• Preprocessor

#### With Examples

Constant Typeswith Examples
Integereg. 2, 10, -2
Decimal (Integer) eg. 2, 10, -2
Octal (Integer)eg. 02, 010
Floating-point/Realeg. -2.4, 4.8
Charactereg. 'i', 'j'
Stringeg. "Hello", "Hi"
Preprocessoreg. #define a 5

#### Integer Constant Types:

1. Decimal Integer Constant
2. Octal Integer Constant
##### Integer Constants
• Integer Constant normal Variable की तरह काम करता है |
• Integer Constant positive (+) या negative (-) हो सकता है |
• Integer Constant की Range -32768 से 32767 तक होती है |

for eg.
Source Code :
```#include <stdio.h>

int main(){

const int num = 5; // integer Constant
printf("integer constant value : %d", num);

return 0;

}
```
Output
```integer constant value : 5
```

##### Character Constants
• Character Constant normal Variable की तरह काम करता है |
• Character Constant सिर्फ single character लेता है | |
• Escape Sequences के साथ भी character constant इस्तेमाल किया जाता है |

Escape SequencesExplaination
\'Single Quotation Mark
\"Double Quotation Mark
\\Backslash
\?Question Mark
\aAudible Bell
\bBackspace
\fForm Feed
\nNew line
\rCarriage Return
\hHorizontal Tab
\vVertical Tab

for eg.
Source Code :
```#include <stdio.h>

int main(){
const char ch = 'H'; // character constant
const char escape[]= "Hello\tWorld"; // Escape sequence - Horizontal Tab and string constant

printf("Character constant : %c\n", ch);
printf("String constant : %s\n", escape);

return 0;
}
```
Output
```Character constant : H
String constant : Hello      World
```

##### Floating-point Constant
• Floating-point Constant normal float variable की तरह ही काम करता है |
• Floating-point Constant में Decimal point (.) होता है |
• अगर Floatint-point Constant की value integer type की हो तो वो Decimal point (.) लेता है |

for eg.
Source Code :
```#include <stdio.h>

int main(){
const float num1 = 5; // floating-point constant with integer value
const float num2 = 3.525984; // Floating-point constant

printf("Floating-point constant : %f\n", num1);
printf("Floating-point constant : %f\n", num2);

return 0;
}
```
Output
```Floating-point constant : 5.000000
Floating-point constant : 3.525984
```

##### String Constant
• String Constant की value Double Quotation Mark (" ") के अंदर लिखी जाती है |
• String Constant Single और Multiple characters लेता है |
• String Constant Escape Sequences के साथ भी इस्तेमाल करते है |

for eg.
Source Code :
```#include <stdio.h>

int main(){
const char str1 []= "H"; // String Constant with single character
const char str2 []= "Hello World"; // Normal String constant
const char str3 [] = "Hello\nWorld"; // String Constant with Escape Sequence

printf("String Constant with single character : %s\n", str1);
printf("Normal String constant : %s\n", str2);
printf("String Constant with Escape Sequence : %s\n", str3);

return 0;
}
```
Output
```String Constant with single character : H
Normal String constant : Hello World
String Constant with Escape Sequence : Hello
World
```

##### Preprocessor Constant
• Preprocessor के साथ भी Constant value रख सकते है |

for eg.
Source Code :
```#include <stdio.h>
#define a 5 // Constant value with preprocessor
#define b 10 // Constant value with preprocessor

int main(){

printf("Value of a  : %d\n", a);
printf("Value of b  : %d", b);

return 0;
}
```
Output
```Value of a  : 5
Value of b  : 10
```