Usage of string.h in c language

string.h is the header file used for string processing in C. It contains the following main functions: copy string: strcpy, strncpy append string: strcat, strncat compare string: strcmp, strncmp find string Length: strlen Search characters: strchr, strrchr

Usage of string.h in C language

string.h is used for characters in C language Standard header files for string processing. It provides a number of functions for manipulating C strings (arrays of characters terminated with '\0').

Main functions

Some of the most commonly used functions in string.h include:

• strcpy: Copy source string to destination characters String
• strncpy: Copies up to n characters from the source string to the destination string, padding the rest with '\0'
• strcat: Append the source string to the end of the target string
• strncat: Append up to n characters from the source string to the end of the target string
• strcmp: Compares two strings and returns 0 (equal), a negative number (the source string is smaller than the target string), or a positive number (the source string is larger than the target string)
• strncmp : Compares the first n characters of two strings, returning 0 (equal), a negative number (the source string is smaller than the target string), or a positive number (the source string is larger than the target string)
• strlen: Returns the length of the string (excluding '\0')
• strchr: Searches the string for the first character matching the specified character
• strrchr: Search for the last character matching the specified character in the string

Usage method

To use the function in string.h, you need Include this header file in your program:

<code class="c">#include <string.h></code>

You can then use functions to manipulate strings. For example, to copy one string into another string, you can use the strcpy function:

<code class="c">char src[] = "Hello";
char dst[5];
strcpy(dst, src);</code>

This copies the contents of the src string into the dst string.

Note

When using the string.h function, you need to pay attention to the following points:

• All string functions assume that the source and target strings have sufficient space to operate.
• The n argument to the strncpy and strncat functions specifies the number of characters to copy or append, excluding '\0'.
• The strcmp and strncmp functions stop comparing when they find the first mismatch in the string.
• strlen function does not include the '\0' character at the end of the string.

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