Array And Strings :STRING (CHARACTER ARRAY)

STRING (CHARACTER ARRAY)

Character Arrays [String]

Strings are stored in C as character arrays terminated by the null character, '\0'.
Declaration of string if done as follows

char str[25];

char str1[30] = "MY STUDYROOM";

M	Y		S	T	U	D	Y	R	O	O	M	\0	............
0	1	2	3	4	5	6	7	8	9	10	11	12	............	29

Assigning a character literal to an array is done as follows.

char str1[] = "MY STUDYROOM";

char str2[] = "Nepal"

The compiler automatically sizes the arrays correctly. For this example, str1 is of length 16, str2 is of length 5.
Example 1: Program to find out the length of string

#include<stdio.h>
#include<conio.h>

main()

{

int len;

char str[25];

printf("Enter any string");

scanf("%s", str);

/*loop has semicolon(;) at the end coz loop doesn't contain any statement below it*/

for(len=0; str[len]!='\0' ; len++);

printf("length of string is %d", len);

getch();

}

Example: Write a program to reverse the string

#include<stdio.h>
#include<conio.h>
#include<string.h>

main()

{

    int i, j, len;

    char str[25], rstr[25];

   

    printf("Enter any string");

    scanf("%s", str);

 

    //finding out the length of string

    len = strlen(str);

 

//reversing the string

for(i=0, j=len-1; j>=0; j--, i++)

          rstr[i] = rstr[j];

 

printf("Reverse sting is %s", rstr);

 

getch();

}

Example : Write a program to find out no. of vowel, consonant, digit, white space and other character in a sentence provided by an user.

#include<stdio.h>
#include<conio.h>

main()

{

    int i, v=0, c=0, d=0, ws=0, oth=0;

    char str[25];

   

    printf("Enter any string");

    scanf("%s", str);

 

    for(i=0; str[i]!='\0' ; i++)

{

if(str[i]=='a'||str[i]=='e'||str[i]=='i'||str[i]=='o'||str[i]=='u')

                v = v + 1;

else

                if(str[i]>='a' && str[i]<='z')

                      c = c + 1;

                else

                      if(str[i]>='0' && str[i]<='9')

                            d = d + 1;

                      else

                            if(str[i]==' ' )

                                  ws = ws + 1;

                            else

                                  oth = oth + 1;

}

  printf(" No. of vowel=%d, Consent=%d, Digit=%d, White space=%d and Other=%d", v, c, d, ws, oth);

  getch();

}

Library Functions for String Manipulation

To use any of these functions in your code, the header file "strings.h" must be included.
strlen():
strlen finds the length of string.
Syntax:

int strlen(char* )

Example:

char str[]="MY STYDYROOM";

int len;
len=strlen(str);

output:

len=12

strcpy():
strcpy copies a string, including the null character terminator from the source string to the destination.
Syntax:

Char* strcpy(char* source_string, char* destination_string)

Example:

char dst[25], src[]="MY STYDYROOM";

strcpy(dst, src);

output:

dst = "MY STYDYROOM"

strcat():
This function appends a source string to the end of a destination string.
Example:

char dst[25]="MY ";

char src[ ] = "STUDYROOM";

strcat(dst, src);

Output:

dst = "MY STYDYROOM"

strcmp
This function compares two strings.

• If the first string is greater than the second, it returns a number greater than zero.
• If the second string is greater, it returns a number less than zero.
• If the strings are equal, it returns 0.

int x;

char str1[25], str2[25];
x = strcmp(str1, str2);

o   x > 0 - if the str1 is greater than str2. [i.e. str1="nepal" and str2="japan" ]
o   x< 0  - if the str1 is less than str2. [i.e. str1="japan" and str2="nepal"]
o   x==0 - if str1 is equal to str2. [i.e. str1="nepal" and str2="nepal" ]

Example: Write a program to find out the string is palindrome or nor.

#include<stdio.h>
#include<conio.h>
#include<string.h>

main()

{

    char str[25], str1[25];

   

    printf("Enter any string");

    scanf("%s", str);

   

    str1 = strrev(str);

 

    if(str==str1)

          printf("Entered string is PALAINDROME");

    else

          printf("Entered string is NOT PALAINDROME");

   getch();

}