62.Strings :Character array, Accepting a string from the keyboard, Printing the string

Strings:

 

char data type:

It is a primary data type used to store a single character constant

It takes 1 byte of memory.

Single character constant must be placed within single quotations.

When a character constant is assigned then its binary equal (ASCII) is stored in the memory.

%c is used to represent character type in I/O statements.

 

Example:

#include<stdio.h>

void main()

{

   char ch='a';

   clrscr();

   printf("%c",ch);

   getch();                                                                                     

}

 

Output:

a

 

NULL character:

In C language '\0' is considered as NULL character.

The ASCII value of '\0' is 0

 

Example:

#include<stdio.h>

void main()

{

  char ch='\0';

  clrscr();

  printf("%d",ch);

  getch();

}

 

Output:

0                                                                                                          

 

Character array:

Set of character constants stored in contiguous memory allocations is called a character array.

When a character array is declared then the C compiler allocates the memory allocation of elements and stores the address of base element in a pointer with the name of character array.

Now the pointer can refer every element using either pointer arithmetics *(x+i) or using index x[i].

 

Example:

#include<stdio.h>

void main()

{

   char x[]={'r','o','c','k','i','n','g'};

   int i;

   clrscr();

   for(i=0;i<7;i++)

     printf("%c",x[i]);

  getch();

}

 

Output:

rocking

 

String:

Any word placed within double quotations is called a string.

In C language there is no data type to handle strings

We need to use a character array to store a string as individual character constants.

When a string is assigned to character array then individual characters are stored in a given sequence and a terminating character '\0' is automatically added.

The size of array is more than the size of string.

 

Example:

#include<stdio.h>

void main()

{

   char x[]="rocking";

   int i;

   clrscr();

   for(i=0;x[i]!='\0';i++)

     printf("%c",x[i]);

   getch();

}

 

Output:

rocking

 

Example explained:

Here the terminating character '\0' is automatically added at the end of string.

The condition (x[i]!='\0') helps to traverse the string without knowing the length.

 

 

Accepting a string from the keyboard:

As we know a string is a combination of characters.

In order to accept a string from the keyboard we need to accept character by character, which is difficult to code.

C language has an automated way of accepting string through scanf() function.

If we specify the address of character array (name) then scanf() accepts character by character and stores in to array.

A terminating character '\0' is automatically added.

Representation character %s is used to represent string in I/O functions.

 

Example:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Printing the string:

Because a string is a combination of characters, it is difficult to code.

The printf() automatically prints the string if the address (name) of character array is given.

 

Example:

printf("%s",x);

 

Specification1:

Accept a string from the keyboard and print by using a loop.

 

Program:

#include<stdio.h>

void main()

{

   char x[50];

   int i;

   clrscr();

   printf("Enter any string:");

   scanf("%s",x);

   printf("The given string:");

   for(i=0;x[i]!='\0';i++)

      printf("%c",x[i]);

  getch();

}

 

Execution:

Enter any string: nice

The given string nice

 

Program explained:

The scanf() accepted the string and automatically stored in character array character by character.

Terminating character '\0' is automatically added.

Character by character is printer until '\0' using a loop.

 

Specification2:

Accept any string from the keyboard and print the same without using a loop.

 

Program:

#include<stdio.h>

void main()

{

   char x[50];

   int i;

   clrscr();

   printf("Enter any string:");

   scanf("%s",x);

   printf("The given string:");

   printf("%s",x);

  getch();

}

 

Execution:

Enter any string: nice

The given string nice

 

Program explained:

Here scanf() and printf() are used to accept and print the strings.

 

Specification3:

Accept any string from the keyboard and print using the function display()

 

Program:

#include<stdio.h>

void display(char*);

void main()

{

   char x[50];

   clrscr();

   printf("Enter any string:");

   scanf("%s",x);

   display(x);

   getch();

}

void display(char *p)                                                                                     

{

  /* int i;

     for(i=0;p[i]!='\0';i++)

            printf("%c",p[i]);  */

 

     printf("%s",p);

}

 

Execution:

Enter any string: india

india

 

Program explained:

Here while sending a string as an argument we specified the name of string (x) as an argument which is the address of array.

A character pointer (p) is defined to store the address of character array.

Now both "x" and "p" refers the same array from different locations.

 

Specification4:

Accept any string from the keyboard and print its length using the function length()

 

Program:

#include<stdio.h>

int length(char*);

void main()

{

   char x[50];

   int l;

   clrscr();

   printf("Enter any string:");

   scanf("%s",x);

   l=length(x);

   printf("The length of string %d",l);

   getch();

}

int length(char *p)

{

  int len,i;

  for(len=0,i=0;p[i]!='\0';i++)

      len++;

  return len;

}

 

Execution:

Enter any string: America

The length of string 7

 

Program explained:

Here we count how many times the loop iterates which is the length of string.

Loop doesn’t iterate when the end of character is reached.