Partial string and character functions in the C language

////main.c//homeWork1230////#include<stdio.h>#include<string.h>#include<ctype.h>intMainintargcConst Char*argv[]) {///The/strstr (STR1,STR2) function is used to determine whether a string str2 is a substring of str1. If it is, the function returns the address that str2 first appears in str1, or null if it is not. //printf ("%s\n", Strstr ("Chinaisgood", "is"));            ////strcmp Compare string sizes based on ASCII. //printf ("%d\n", Strcoll ("Chinaisgood", "as"));            /*function Description: strcspn () computes consecutive characters from the beginning of the argument s string, and these characters are not in the string that the parameter reject refers to. In short, if the value returned by STRCSPN () is n, then the string s starts with a continuous n Characters in the string reject are not included in each character.*/ //printf ("%lu\n", strcspn ("Chinais good", "in")); //one is to find the position of a character in a string, and the other is to find the position of a string in another string, strstr. //printf ("%s\n", STRCHR ("abcdefghijklmnopqrstuvwxyz", ' C ')); //Copy//Char *b;//b=strdup ("AFNKSF");//printf ("%s\n", b); //S1,s2 is a string when memcmp (s1,s2,1) is the first byte of the comparison S1 and S2 ASCII code value;//printf ("%d\n", memcmp ("AVC", "DDS", 1)); //used to find the C string needle in the C string haystack, ignoring the case. A char pointer that returns the position of the first occurrence of the needle string in the haystack string if found//printf ("%s\n", Strcasestr ("Ffdsafds", "D")); //you can see what this is all about, this function, which is not implemented in most of the OS .//strnstr function Description, find S2 in the first pos1 string of S1, if present, return S2 in S1 position, if not found, return NULL, Test no problem//printf ("%s\n", Strnstr ("ABCD", "C", 2)); //Copy//Char *s= "Golden Global View";//Char d[20];//    //   //clrscr ();//    //stpcpy (d,s);//printf ("%s\n", D); //copy, only to Nth//Char *s= "Golden Global View";//Char d[20];//strlcpy (d, S, 6);//printf ("%s\n", D); //character Functions//determines whether the character variable C is a letter or a number, or returns a nonzero if it returns 0//printf ("%d\n", Isalnum (' $ ')); //used to determine if a character is a tab or a space, or nonzero if it returns 0//printf ("%d\n", Isblank (')); //function: Determine if character C is a control character//Note: When C is between 0x00-0x1f or equal to 0x7f (DEL), it returns a value other than 0, otherwise zero is returned. //printf ("%d\n", Iscntrl (' \ n ')); //determine if it is a printable character//printf ("%d\n", Isgraph (' $ ')); //Judging if it's a punctuation mark//printf ("%d\n", ispunct (' a ')); //Check if parameter C is a space character, that is, to determine whether it is a space ('), a horizontal position character//(' \ t '), return key (' \ R '), newline (' \ n '), vertical position character (' \v '), or page turn (' \f ')//printf ("%d\n", Isspace (' a ')); //to turn a character into an ASCII value//printf ("%d\n", Toascii (' a ')); //converts a character's number to an integral type//printf ("%d\n", Digittoint (' 9 ')); //determines whether a character is a number//printf ("%d\n", Isnumber (' 4 ')); //determines whether a character is between 0 and 127, whether it is ASCII//printf ("%d\n", Isascii (' n '));                return 0;}

Partial string and character functions in the C language