A string is a sequence of character that is treated as a single data item.
Any group of characters defined between double quotation mark is a string constant.
Declaring String Variable
C does not support string as a data type. However, it allows us to represent strings as character array.
| The general form of declaration is:
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where:
char
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character defined data-type
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| string-name
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user-defined string name
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| size
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determine the number of characters
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in the string name.
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Examples
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char city[10]; |
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char name[10];
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When the compiler assigns a character string to a character array,
it automatically supplies a null character (‘\0’) at the end of the string. Therefore,
the size should be equal to the maximum number of character in the string plus one.
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Initialization of String
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Character arrays may be initialized when they are declared.
- char name[6] = “Mohan”;
- char name[6] = {‘M’, ‘o’, ‘h’, ‘a’, ‘n’, ;\0’};
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C permits us to initialize a character array without specifying the number of elements.
In such case, the size of array will be determined automatically.
- char string[ ] = {‘G’, ‘O’, ‘O’, ‘D’, ‘\0’};
String – Handling Function
The C library supports a large number of string handling functions that can be used to carry out many of the string manipulations.
Following are the most commonly used string-handling functions.
strcat()
- The strcat() function joins two string together.
| The general form of declaration is:
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where:
string2 appended to string1
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it does so by removing the null character at the end of string1 and placing string2 from there. The string at string2 remains unchanged.
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strcmp()
This is a function which compares two strings to find out whether they are same or different.
If the two string are identical, strcmp() returns a value zero. If they’re not,
it returns the numeric difference between the ASCII values of the first non-matching pair of characters.
where:
string1 and string2
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may be string variable or string constants
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strcpy()
The strcpy function work almost like a string-assignment operator.
This function copies the contents of one string into another.
It assign the contents of string2 to string1. string2 may be a character array variable or a string constant.
strlen()
This function counts and returns the number of characters in a string.
where:
n
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is an integer variable which receive the value of the length of the string.
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Other - String Function
| Functions | Descriptions |
| strlwr() | Convert a string to lowercase |
| strupr() | Convert a string to uppercase |
| strncpy() | Copies first n characters of one string into another |
| stricmp() | Compares two string without regard to case (identical to strcmp) |
| strnicmp() | Compares first n characters of two strings without regard to case. |
| strchr() | Find the last occurrence of a given character in a string. |
| strstr() | Find the first occurrence of a given string in another string. |
| strrev() | Reverses string. |
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