C and c ++ strings

C and c ++ strings
Name: strcpy

Function: copy a string.

char* strcpy(char* dest, const char* src){    if(dest == NULL || src == NULL)    {        return NULL;    }    char* tmp = dest;    while((*tmp++ = *src++) != '\0');    return dest;}

Name: strncpy

Function: copy a string.

Strncpy copies the first n characters of the string that src points to ending with '\ 0' to the array indicated by dest, and returns the pointer to dest.

Note:

When n> = sizeof (src), the copy is correct and '\ 0' is added to the end of the dest string ';

When n

char* strncpy(char* dest, const char* src, size_t count){    if(dest == NULL || src == NULL)    {        return NULL;    }    char* tmp = dest;    while(count--)    {        *dest++ = *src++;    }    return tmp;}

Name: strcmp

Function: Compares strings.

int strcmp(const char* s0, const char* s1){    int ret = 0;    unsigned char c1,c2;    while(1)    {        c1 = *s0++;        c2 = *s1++;        if(c1 != c2)        {            return c1 > c2 ? 1 : -1;        }        if(!c1)        {            break;        }    }    return ret;}

Name: strncmp

Function: Compares strings.

int strncmp(const char* s0, const char* s1, size_t count){    int ret = 0;    unsigned char c1,c2;    while(count)    {        c1 = *s0++;        c2 = *s1++;        if(c1 != c2)        {            return c1 > c2 ? 1 : -1;        }        if(!c1)        {            break;        }        count--;    }    return ret;}

Name: reserve

Function: String Inversion

void reserve(char* word){    if(word != NULL)    {        char* start = word;        char* end = word;        while(*end++);        end -= 1;        while(start < end)        {            char s = *start;            *start = *end;            *end = s;            start++;            end--;        }    }}

Name: reserveWords

Function: String Inversion

I love you -----> you love I

void reserveWords(){    char words[] = "I love You";    reserve(words);        char* start = words;    char* end = words;    while(*end != '\0')    {        if(*end == '\0' || *end == ' ')        {            char tmp[20];            memcpy(tmp, start, end - start);            reserve(tmp);            start = end;        }        else if(*end == ' ')        {            start++;            end++;        }        else        {            end++;        }    }}