Linux Common C functions (memory and string operation 2) __oracle

strcat (connecting two strings)
Related functions
bcopy,memccpy,memcpy,strcpy,strncpy

Table header File
#include <string.h>

Defining functions
Char *strcat (char *dest,const char *src);

Function description
strcat () copies the parameter src string to the end of the string referred to by the parameter dest. The first argument dest to have enough space to hold the string to be copied.

return value
Returns the string start address of the parameter dest

Example
#include <string.h.>
Main ()
{
Char a[30]= "string (1)";
Char b[]= "string (2)";
printf ("Before strcat ():%s/n", a);
printf ("After strcat ():%s/n", strcat (a,b));
}

Perform
Before Strcat (): string (1)
After strcat (): String (1) string (2)
　

STRCHR (finds the first occurrence of the specified character in the string)
Related functions
Index,memchr,rinex,strbrk,strsep,strspn,strstr,strtok

Table header File
#include <string.h>

Defining functions
char * STRCHR (const char *s,int c);

Function description
STRCHR () is used to find the first parameter C address that appears in the parameter S string, and then returns the address where the character appears.

return value
If the specified character is found, the address of the character is returned, or 0 is returned.

Example
#include <string.h>
Main ()
{
Char *s=0123456789012345678901234567890 ";
Char *p;
P=STRCHR (S, ' 5 ');
printf ("%s/n", p);
}

Perform
5.68E+25
　

strcmp (comparison string)
Related functions
Bcmp,memcmp,strcasecmp,strncasecmp,strcoll

Table header File
#include <string.h>

Defining functions
int strcmp (const char *s1,const char *S2);

Function description
strcmp () is used to compare parameter S1 and S2 strings. The comparison of string sizes is based on the order of the ASCII code table, which is also the value of the character. strcmp () First S1 the first character value minus S2 First character value, if the difference is 0 then continue to compare the next character, if the difference is not 0 will return the difference value. For example, the string "Ac" and "ba" Comparisons return the Difference (-33) of the character "A" (65) and ' B ' (98).

return value
Returns 0 if the parameter S1 and the S2 string are the same. S1 returns a value greater than 0 if it is greater than S2. S1 returns a value less than 0 if it is less than S2.

Example
#include <string.h>
Main ()
{
Char *a= "ABcDeF";
Char *b= "AbCdEf";
Char *c= "Aacdef";
Char *d= "ABcDeF";
printf ("strcmp (a,b):%d/n", strcmp (a,b));
printf ("strcmp (a,c):%d/n", strcmp (A,c));
printf ("strcmp (a,d):%d/n", strcmp (a,d));
}

Perform
strcmp (a,b): 32
strcmp (a,c):-31
strcmp (a,d): 0