The role of strlen in c language

The strlen function is used to calculate the length of the C language string, excluding the terminator '\0'. Specific principle: 1. The function traverses the string until it encounters the terminator '\0'. 2. Count the number of characters from the beginning of the string to the terminator. 3. Return the length of the string (type size_t). For example: strlen("Hello World") returns 11.

The role of strlen in C language

strlen function is a C language library Function used to obtain the length of a string, that is, the number of characters in the string (excluding the terminator '\0').

Principle of operation:

strlen The function traverses the string until it encounters the terminator '\0'. It determines the length of a string by counting the number of characters from the beginning of the string to the terminator.

Function prototype:

<code class="C">size_t strlen(const char *str);</code>

Parameters:

• str: Pointer to be calculated Pointer to the length of the string.

Return value:

• strlen The function returns the length of the string (type is size_t ).

Example usage:

<code class="C">#include <stdio.h>
#include <string.h>

int main() {
    char str[] = "Hello World";
    size_t len = strlen(str);
    printf("The length of the string '%s' is: %d\n", str, len);
    return 0;
}</code>

Output:

<code>The length of the string 'Hello World' is: 11</code>

Note:

• strlen The function does not modify the original string.
• It returns the byte length of the string, not the Unicode-encoded character length.
• If the string is NULL, the strlen function returns 0.

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