nous allons présenter la librairie qui va permettre de gérer les chaines de caractères.

C'est l'occasion de  voir comment utiliser une librairie mise à disposition 

#include <string.h>

Le fichier source , string.c est disponible sur github de Linus Torvald

man 3 string.h

string.h(3avr)                                                  avr-libc                                                  string.h(3avr)

NAME

       string.h

SYNOPSIS

   Macros

       #define _FFS(x)

   Functions

       int ffs (int __val)

       int ffsl (long __val)

       __extension__ int ffsll (long long __val)

       void * memccpy (void *, const void *, int, size_t)

       void * memchr (const void *, int, size_t) __ATTR_PURE__

       int memcmp (const void *, const void *, size_t) __ATTR_PURE__

       void * memcpy (void *, const void *, size_t)

       void * memmem (const void *, size_t, const void *, size_t) __ATTR_PURE__

       void * memmove (void *, const void *, size_t)

       void * memrchr (const void *, int, size_t) __ATTR_PURE__

       void * memset (void *, int, size_t)

       char * strcat (char *, const char *)

       char * strchr (const char *, int) __ATTR_PURE__

       char * strchrnul (const char *, int) __ATTR_PURE__

       int strcmp (const char *, const char *) __ATTR_PURE__

       char * strcpy (char *, const char *)

       int strcasecmp (const char *, const char *) __ATTR_PURE__

       char * strcasestr (const char *, const char *) __ATTR_PURE__

.....

man 3 strlen()

strlen(3)                                               Library Functions Manual                                               strlen(3)

NAME

       strlen - calculate the length of a string

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <string.h>

       size_t strlen(const char *s);

DESCRIPTION

       The strlen() function calculates the length of the string pointed to by s, excluding the terminating null byte ('\0').

RETURN VALUE

       The strlen() function returns the number of bytes in the string pointed to by s.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐

       │Interface                                                                                             │ Attribute     │ Value   │

       ├──────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤

       │strlen()                                                                                              │ Thread safety │ MT-Safe │

       └──────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

source de la fonction strlen en C par Linus Torvald

size_t strlen(const char *s)

{

const char *sc;

for (sc = s; *sc != '\0'; ++sc)

/* nothing */;

return sc - s;

}

man 3 strcpy

strcpy(3)                                               Library Functions Manual                                               strcpy(3)

NAME

       stpcpy, strcpy, strcat - copy or catenate a string

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <string.h>

       char *stpcpy(char *restrict dst, const char *restrict src);

       char *strcpy(char *restrict dst, const char *restrict src);

       char *strcat(char *restrict dst, const char *restrict src);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       stpcpy():

           Since glibc 2.10:

               _POSIX_C_SOURCE >= 200809L

           Before glibc 2.10:

               _GNU_SOURCE

DESCRIPTION

       stpcpy()

       strcpy()

              These  functions  copy the string pointed to by src, into a string at the buffer pointed to by dst.  The programmer is re‐

              sponsible for allocating a destination buffer large enough, that is, strlen(src) + 1.  For the difference between the  two

man 3 strcmp

strcmp(3)                                               Library Functions Manual                                               strcmp(3)

NAME

       strcmp, strncmp - compare two strings

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <string.h>

       int strcmp(const char *s1, const char *s2);

       int strncmp(const char s1[.n], const char s2[.n], size_t n);

DESCRIPTION

       The  strcmp()  function compares the two strings s1 and s2.  The locale is not taken into account (for a locale-aware comparison,

       see strcoll(3)).  The comparison is done using unsigned characters.

       strcmp() returns an integer indicating the result of the comparison, as follows:

       •  0, if the s1 and s2 are equal;

       •  a negative value if s1 is less than s2;

       •  a positive value if s1 is greater than s2.

       The strncmp() function is similar, except it compares only the first (at most) n bytes of s1 and s2.