SINOPSIS
#include <strings.h>
int strcasecmp(const char *s1, const char *s2);
int strncasecmp(const char *s1, const char *s2, size_t n);
char *index(const char *s, int c);
char *rindex(const char *s, int c);
#include <string.h>
char *strcat(char *dest, const char *src);
char *strchr(const char *s, int c);
int strcmp(const char *s1, const char *s2);
int strcoll(const char *s1, const char *s2);
char *strcpy(char *dest, const char *src);
size_t strcspn(const char *s, const char *reject);
char *strdup(const char *s);
char *strfry(char *string);
size_t strlen(const char *s);
char *strncat(char *dest, const char *src, size_t n);
int strncmp(const char *s1, const char *s2, size_t n);
char *strncpy(char *dest, const char *src, size_t n);
char *strpbrk(const char *s, const char *accept);
char *strrchr(const char *s, int c);
char *strsep(char **stringp, const char *delim);
size_t strspn(const char *s, const char *accept);
char *strstr(const char *haystack, const char *needle);
char *strtok(char *s, const char *delim);
size_t strxfrm(char *dest, const char *src, size_t n);