Reference
C Library
IOstream Library
Strings library
STL Containers
STL Algorithms
Miscellaneous
C Library
cassert (assert.h)
cctype (ctype.h)
cerrno (errno.h)
cfloat (float.h)
ciso646 (iso646.h)
climits (limits.h)
clocale (locale.h)
cmath (math.h)
csetjmp (setjmp.h)
csignal (signal.h)
cstdarg (stdarg.h)
cstddef (stddef.h)
cstdio (stdio.h)
cstdlib (stdlib.h)
cstring (string.h)
ctime (time.h)
cstring (string.h)
functions:
memchr
memcmp
memcpy
memmove
memset
strcat
strchr
strcmp
strcoll
strcpy
strcspn
strerror
strlen
strncat
strncmp
strncpy
strpbrk
strrchr
strspn
strstr
strtok
strxfrm
macros:
NULL
types:
size_t


strlen

function
<cstring> 
size_t strlen ( const char * str );

Get string length

Returns the length of str.

The length of a C string is determined by the terminating null-character: A C string is as long as the amount of characters between the beginning of the string and the terminating null character.

This should not be confused with the size of the array that holds the string. For example:

char mystr[100]="test string";
defines an array of characters with a size of 100 chars, but the C string with which mystr has been initialized has a length of only 11 characters. Therefore, while sizeof(mystr) evaluates to 100, strlen(mystr) returns 11.

Parameters

string
C string.

Return Value

The length of string.

Example

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/* strlen example */
#include <stdio.h>
#include <string.h>
int main ()
{
  char szInput[256];
  printf ("Enter a sentence: ");
  gets (szInput);
  printf ("The sentence entered is %u characters long.\n",strlen(szInput));
  return 0;
}


Output:

Enter sentence: just testing
The sentence entered is 12 characters long.

See also

strcmp Compare two strings (function)
strchr Locate first occurrence of character in string (function)
strrchr Locate last occurrence of character in string (function)