NULL Character : Terminating Character in String

We have already studied how string is declared and initialized now in this chapter we will be learning about terminating character of String i.e NULL Character.

Why do we need Terminating Character ?

1. C Programming does not provide inbuilt ‘String‘ data type. [See Available Data Types in C]
2. String is one of the most important and necessary Data Structure in C Programming
3. We can say String as Variable length Structure stored in Fixed Length Structure
4. Array Size is not the Actual Length of the String , So to recognize the End of the String we use NULL character
   

Pictorial Understanding :

Explanation :

In the above picture we can see -

1. Before Initializing String it Contain Garbage Characters.
2. Length of String [i.e Declared character array] is 7 so it Contain 7 Garbage Characters.
3. When we attempt to store “CAT” in the string of Character length 7 then String Would be “CAT@’af“

Packing Up : Summary

Reading String with spaces by using scanf
Note that -

1. scanf with %s accepts only String which does not contain whitespaces (blanks/space)
2. C Supports the ‘ special Edit set Conversion Code ‘ , by using this method we can accept the line of String with spaces using scanf
3. It Reads wide verity of Characters including blank

Syntax :

scanf("%[\^n]", name );

Live Example :

char name[100];
printf("\nEnter the name : ");
scanf("%[\^n]",name);
printf ("\nName of Student : %s ",name);

Output of this Block :

Enter the Name : Don Bosqo
Name of Student : Don Bosqo

Arithmetic Operations On Character :

• C Programming Allows you to Manipulate on String
• Whenever the Character is variable is used in the expression then it is automatically Converted into Integer Value called ASCII value
• All Characters can be Manipulated with that Integer Value.(Addition,Subtraction)

Examples :

1. ASCII value of : ‘a’ is 97
2. ASCII value of : ‘z’ is 121

Possible Ways of Manipulation :
Way 1: Displays ASCII value[ Note that %d in Printf ]

char x = 'a';
printf("%d",x); // Display Result = 97

Way 2 : Displays Character value[ Note that %c in Printf ]

char x = 'a';
printf("%c",x); // Display Result = a

Way 3 : Displays Next ASCII value[ Note that %d in Printf ]

char x = 'a' + 1 ;
printf("%d",x);
// Display Result = 98 ( ascii of 'b' )

Way 4 Displays Next Character value[Note that %c in Printf ]

char x = 'a' + 1;
printf("%c",x); // Display Result = 'b'

Way 5 : Displays Difference between 2 ASCII in Integer[Note %d in Printf ]

char x = 'z' - 'a';
printf("%d",x);
/* Display Result = 25 
    (difference between ASCII of z and a ) */

Way 6 : Displays Difference between 2 ASCII in Char [Note that %c in Printf ]

char x = 'z' - 'a';
printf("%c",x);
/* Display Result = ↓ 
      ( difference between ASCII of z and a ) */

Putchar function : Displaying String in C Programming
Syntax :

int putchar(int c);

Way 1 : Taking Character as Parameter

putchar('a') ;  // Displays : a

1. Individual Character is Given as parameter to this function.
2. We have to explicitly mention Character.

Way 2 : Taking Variable as Parameter

putchar(a); 
// Display Character Stored in a

1. Input Parameter is Variable of Type “Character”.
2. This type of putchar() displays character stored in variable.

Way 3 : Displaying Particular Character from Array

putchar(a[0]) ;  
// Display a[0] th element from array

1. Character Array or String consists of collection of characters.
2. Like accessing individual array element , characters can be displayed one by one using putchar().

Live Example :

#include< stdio.h>
#include< conio.h>
void main()
{
   char string[] = "This is an example string\n";
   int i=0;
   clrscr();
   while(string[i]!='\0')
   {
     putchar(string[i]);
     i++;
   }
getch();
}

1. Display String Character by Character
2. Header File : stdio.h
3. Putchar is a macro that outputs a character on stdout.

Related Articles :

1. How to Input Password in C : Validation of User name
2. Putchar function >> Displaying String in C
3. Puts >> Displaying String in C Programming
4. Printf >> Displaying String in C Programming

Puts >> Displaying String in C Programming :
Way 1 :Messaging

puts(" Type your Message / Instruction ");

• Like Printf Statement puts() can be used to display message.

Way 2 : Display String

puts(string_Variable_name) ;

1. puts is included in header file “stdio.h”
2. As name suggest it used for Printing or Displaying Messages or Instructions

1. Printing Message
2. Ask user for entering the data ( Labels . Instructions )
3. Printing Results

#include< stdio.h>
#include< conio.h>
void main()
  {
   char string[] = "This is an example string\n";
   puts(string);     // String is variable Here
   puts("String");   // String is in Double Quotes
   getch();
}

Output :

String is : This is an example string
String is : String

Related Articles :

1. How to Input Password in C : Validation of User name
2. Putchar function >> Displaying String in C
3. Puts >> Displaying String in C Programming
4. Printf >> Displaying String in C Programming

Printf >> Displaying String in C Programming :

• Way 1 : Messaging

printf (" Type your Message / Instruction " ) ;

• Way 2 : Display String

printf ("Name of Person is %s ", name ) ;

1. printf is included in header file “stdio.h”
2. As name suggest it used for Printing or Displaying Messages or Instructions

Uses :

1. Printing Message
2. Ask user for entering the data ( Labels . Instructions )
3. Printing Results

Live Example :

#include<stdio.h>
#include<conio.h>
void main()
{
char str[10];
printf("Enter the String : ");
scanf("%s",str);  // Accept String
printf("String is : %s ",str);
getch();
}

Output :

Enter the String : Pritesh
String is : Pritesh

Related Articles :

1. How to Input Password in C : Validation of User name
2. Putchar function >> Displaying String in C
3. Puts >> Displaying String in C Programming
4. Printf >> Displaying String in C Programming

getchar() : Reading or Accepting String Character by Character

In C Programming we have many input/output functions that are useful for accepting input from the user. i.e scanf() | gets(). Getchar() function is also one of the function which is used to accept the single character from the user.
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Note :

The characters accepted by getchar() are buffered until RETURN is hit means getchar() does not see the characters until the user presses return. (i.e Enter Key)
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Syntax for Accepting String and Working :

/* getchar accepts character & stores in ch */
char ch = getchar();

When control is on above line then getchar() function will accept the single character. After accepting character control remains on the same line. When user presses the enter key then getchar() function will read the character and that character is assigned to the variable ‘ch’.

getchar() Example 1 :

In the following example we are just accepting the single character and printing it on the console -

main()
{
   char ch;
   ch = getchar();
   printf("Accepted Character : %c",ch);
}

Output :

Accepted Character : A

getchar() Example 2 : Accepting String (Use One of the Loop)

#include<stdio.h>
void main()
{
int i = 0;
char name[20]; 
printf("\nEnter the Name : "); 
while((name[i] = getchar())!='\n')
        i++ ;
getch();
}

Explanation of the above Program :

while((name[i] = getchar())!='\n')
        i++ ;

above while loop will accept the one character at a time and check it with newline character. Whenever user enters newline character then control comes out of the loop.