Just a little summary The function name: stpcpy Function: copy one string to another, stop at ‘\0’, destin must have enough space Usage: char *stpcpy(char *destin, char *source);

The function name: strcat Power: string concatenation function, note that destin has plenty of space Usage: char *strcat(char *destin, char *source);

The function name: strchr Function: looking for the first match of a given character in a string, NULL cannot be found Usage: char *strchr(char *str, char c);

The function name: strcmp Power: string size comparison, str1 > str2 returns 1, str1 < str2 returns negative 1, equal returns 0 Usage: int strcmp(char *str1, char *str2);

The function name: strncmpi Power: compare the first maxlen characters of the strings str1 and str2, ignoring case Usage: int strncmpi(char *str1, char *str2, unsigned maxlen);

The function name: strcpy Work: stop copying when ‘\0’ is encountered. destin must have enough space Usage: char *strcpy(char *str1, char *str2);

The function name: strcspn Function: returns the value of the first character in the string s1 that appears in s2 in s1, that is, the length of the substring that appears in s1 but not in s2 Usage: int strcspn(char *str1, char *str2); Application: str1=“Golden Global View”; str2 = “new” In s1, and in s2, n e w is satisfied, while e is the first to appear in s1, so it returns its position

The function name: strdup Power: copy the string to the new location. Note that when using this function, a new piece of memory is requested, so it must be freed after use Usage: char *strdup(char *str); Application:

#include <stdio.h>
#include <string.h>
#include <alloc.h>
int main(void)
{
  char *dup_str, *string = "abcde";
  dup_str = strdup(string);	//  To apply for the 1 Slice the new memory address, dup_str It points to this piece of memory
  printf("%s\n", dup_str);
  free(dup_str);		// 1 Need to release
  return 0;
}

The function name: stricmp Power: compare string sizes, ignoring case Usage: int stricmp(char *str1, char *str2);

The function name: strerror Power: returns a pointer to an error message string Usage: char *strerror(int errnum); Application:

#include <stdio.h>
#include <errno.h>
int main(void)
{
  char *buffer;
  buffer = strerror(errno);
  printf("Error: %s\n", buffer);
  return 0;
}

The function name: strcat0 Power: compare two strings, ignoring case Usage: int strcmpi(char *str1, char *str2);

The function name: strncmp Power: compare string size maxlen is the number of bits to compare Use: int strncmp(char *str1, char *str2, int maxlen);

The function name: strncmpi Function: compare the first part of a string to the first part of another string, case or case. maxlen is the number of bits to compare Usage: int strncmpi(char *str1, char *str2,int maxlen);

The function name: strncpy Power: string copy maxlen to specify how many bits to copy Use: char *strncpy(char *destin, char *source, int maxlen);

The function name: strnicmp Function: ignore case comparison string maxlen is the number of digits to compare Use: int strnicmp(char *str1, char *str2, unsigned maxlen);

The function name: strnset Function: sets the first n characters in a string to the specified character ch Usage: char *strnset(char *str, char ch, unsigned n);

The function name: strpbrk Function: find the position in the source string (s1) that first contains any of the characters in the search string (s2) and return, or if not, a null pointer Usage: char *strpbrk(char *str1, char *str2);

The function name: strrchr Function: looks for the last occurrence of a specified character in a string Use: char *strrchr(char *str, char c);

The function name: strrev Work: string inversion Usage: char *strrev(char *str);

The function name: strset Power: sets all characters in a string to the specified character Use: char *strset(char *str, char c);

The function name: strspn Function: returns the first subscript of the string str1 that does not appear in the specified string str2 Usage: int strspn(char *str1, char *str2);

The function name: strstr Function: looks for the first occurrence of a specified string in a string Usage: char *strstr(char *str1, char *str2);

The function name: strtok Function: finds the word separated by the delimiter specified in the second string Usage: char *strtok(char *str1, char *str2); Application:

#include<iostream>
#include<cstring>
using namespace std;
int main()
{
  char sentence[]="This is a sentence with 7 tokens";
  cout<< "The string to be tokenized is:\n"<< sentence <<"\n\nThe tokens are:\n\n";
  char *tokenPtr=strtok(sentence," ");
  while(tokenPtr!=NULL)
	{
    cout<<tokenPtr<<endl;
    tokenPtr=strtok(NULL," "); //  When called again, no 1 The parameters and NULL
  }

}

The function name: strupr Function: converts lowercase letters in a string to uppercase letters Usage: char *strupr(char *str);

The function name: swab Power: bytes exchanged, nbytes is the number of bytes exchanged Usage: void swab (char *from, char *to, int nbytes); Application:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
char source[15] = "Frank Borland";
char target[15];
int main(void)
{
  swab(source, target, strlen(source));
  printf("This is target: %s\n", target);
  return 0;
}

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