string.h manipulation

							STRING MANIPULATION



                         Presented by:
             Engr. Adrian S. Valmocina
INITIALIZATION OF STRING



    char var_name[index]

    Where:

    Char = data type of the string
    var_name = name of the string container to be
    used
    index = length/capacity of the string container
Ways to assign a value to a string container/variable



     >> Direct assignment/ declaration
            > char string[] = “String to be assigned”

     >> Via user input
           > gets(var_name)
 GETS
gets ( char str )
>>Get string from stdin

>>Reads characters from stdin and stores them as a string into str until
a newline character ('\n') or the End-of-File is reached.

>>The ending newline character ('\n') is not included in the string.

>>A null character ('\0') is automatically appended after the last
character copied to str to signal the end of the C string.

>>Notice that gets does not behave exactly as fgets does with stdin as
argument: First, the ending newline character is not included with gets
while with fgets it is..
PRINTING A STRING ON THE SCREEN


>>printf (“%s”, str)


>>puts(str)

       where:
                str = string container/ variable
PUTS
                    char puts (char *string );
 >>Write string to stdout

 >>Writes the C string pointed by str to stdout and appends a
 newline character ('\n').

 >>The function begins copying from the address specified
 (str) until it reaches the terminating null character ('\0'). This
 final null-character is not copied to stdout.

 Using fputs(str,stdout) instead, performs the same operation
 as puts(str) but without appending the newline character at
 the end.
STRING FUNCTIONS (STRING.H)

   >> strcmp

   >> strcat

   >> strcpy

   >> strlen
STRLEN

   Declaration:

                   int strlen( char *string)

   Where:
        string to be tested

   >>Strlen returns the length of a string in integer
   value.
  STRCPY
Declaration:

               char *strcpy(char *destination, char *source);

Where:
     *destination >> output string
       *source>> the container of the string to be copied

>>Strcpy copies one string to another. The destination must be
large enough to accept the contents of the source string
STRCMP

 Declaration:

            int strcmp(char *string1, char *string2);

 Where:
      string1,string2 >> string containers to be
 compared

 >> Strcmp compares two strings and returns an integer
 indicating the difference between the strings. If the
 strings match, then the number returned is 0.
STRCAT
Declaration:

          char *strcpy(char *destination, char *source);

Where:
       destination >> the string container that will get the resulting
concatenation
       source >> string to be appended at the end of *destination

>> Strcat combines two strings and returns a pointer to the
destination string. In order for this function to work (and not seg
fault), you must have enough room in the destination for both
strings.
STRDUP
Declaration:

                       char *strdup(*source);

Where:

         source >> string to copied

>> strdup makes a duplicate of string source
>> string allocation length = strlen(source) + 1
STRLWR, STRUPR
Declaration:

                      char *strlwr(char *string);
                      char *strupr(char *string);

Where:
         string>> string to be converted

>> Strlwr converts uppercase letters (A-Z) into lowercase letters
>> Strupr converts lowercase letters (a-z) into uppercase letters
STRCHR
Declaration:

                 char *strchr(char *string, char c);

Where:
         string >> the string to be searched
         c >> character to be searched from the string

>> Strchr scans a string in the forward direction, looking for a
specific character
>> strchr finds the first occurrence of the character c in the string
STRRCHR
Declaration:

                 char *strrchr(char *string, char c);

Where:
         string >> the string to be searched
         c >> character to be searched from the string

>> Strrchr scans a string in the reverse direction, looking for a
specific character
>> strrchr finds the last occurrence of the character c in the string
STRREV
Declaration:

                      char *strrev(char *string);

Where:
         string >> string to be reversed

>> strrev changes the characters in a string to reverse order,
except the terminating null character.
>> strrev returns a pointer to the reversed string
STRSPN, STRCSPN
Declaration:

            char *strspn(char *string1, char *string2);
            char *strspn(char *string1, char *string2);


>> Strspn finds the initial segment of string1 that consists entirely
of characters from string2.
>> Strspn finds the initial segment of string1 that consists entirely
of characters NOT from string2.
STRSTR
Declaration:

               char *strstr(char *string1, char *string2);

>> strstr scans string1 for the first occurrence of the substring
string2

>> on success, returns a pointer to the element in string1 where
string2 begins (points string2 in string1)
THANK YOU!




                     Presented by:
         Engr. Adrian S. Valmocina