String Manipulation Functions

String Manipulation functions allow you to manipulate or compare strings. These functions begin with the str prefix. Expand the category to view a list of the available functions.

strdup //字符串复制

strlwr //转换为小写字符

strupr //转换为大写字符

strncat//连接n个字符到另一字符串

strcat

//char *strcat(char *to,const char *from);

char fullpath[1024],*filename="logfile.txt";

strcpy(fullpath,"c:\\tmp\\");//字符串复制

strcat(fullpath,filename);//字符串连接

lr_output_message("Full path of file is %s",fullpath);

strchr

strrchr

char *string ="His Excellency the Duke of Exeter";

char *first_x,*last_x;

//获取搜索字符第一次出现的位置以后的字符串，如：xcellency the Duke of Exeter

first_x=(char *)strchr(string,'x');

lr_output_message("The first occurrence of x: %s",first_x);

//获取搜索字符最后一次出现的位置以后的字符串，如：xeter

last_x=(char *)strrchr(string,'x');

lr_output_message("The last occurrence of x: %s",last_x);

strlen

   int is_digit, i = 0;

   char * str = "1234567k89";

   unsigned int len = strlen(str);

   do {

       if (i == len) {

           lr_output_message ("No letters found in string");

           return -1;

       }

                  //isdigit函数，返回十进制数非0(true),返回0(false)

       is_digit = isdigit(str[i++]);

   }

         //当为0是循环条件终止

   while (is_digit);

       lr_output_message ("The first letter appears in character %d of string", i);}

strcmp

stricmp

strncmp

strnicmp

int result;

char tmp[20];

char string1[]="The quick brown dog jumps over the lazy fox";

char string2[]="The QUICK brown dog jumps over the lazy fox";

//大小写敏感(小写>大写)

result = strcmp(string1,string2);

if(result>0)

    strcpy(tmp, "greater than");

   else if(result < 0)

    strcpy(tmp, "less than");

   else

    strcpy(tmp, "equal to");

lr_output_message("strcmp：String1 is %s string2",tmp);

//大小写不敏感(小写=大写)

result = stricmp(string1,string2);

if( result > 0 )

       strcpy( tmp, "greater than" );

   else if( result < 0 )

       strcpy( tmp, "less than" );

   else

       strcpy( tmp, "equal to" );

lr_output_message( "stricmp: String 1 is %s string 2", tmp);

         //比较string1和string2前30个字符，大小写敏感

   result = strncmp( string1, string2 , 30);

   if (result > 0 )

       strcpy(tmp, "greater than");

   else if (result < 0)

       strcpy(tmp, "less than");

   else

       strcpy(tmp, "equal to");

lr_output_message ("strncmp: String 1 is %s string 2", tmp);

         //比较string1和string2前30个字符，大小写不敏感

         result = strnicmp( string1, string2 , 30); 

   if (result > 0 )

       strcpy( tmp, "greater than");

   else if (result < 0)

       strcpy(tmp, "less than");

   else

       strcpy(tmp, "equal to");

   lr_output_message ("strnicmp: String 1 is %s string 2", tmp);

strset

         char str[16];

   strcpy(str, "Fill me in");

   lr_output_message ("Before strset str=%s", str);

         lr_output_message("%d",strlen(str));//字符串长度为10

         //用字符'x'填充

   strset(str, 'x');

   lr_output_message ("After strset str=%s", str);

strspn

  char * str = "corroborative";

   int rc;

         //返回字符串'corroborative'首位是否包含'ro'

   if ((rc = strspn(str, "ro")) == 0)

       lr_output_message ("No o's or r's found");

   else

       lr_output_message ("%d of %d characters are an o or an r", rc, strlen(str));

         //返回字符串'corroborative'首位+1是否包含'ro'

   if ((rc = strspn(str + 1, "ro")) == 0)

       lr_output_message ("No o's or r's found");

   else

       lr_output_message ("%d of %d characters are an o or an r", rc, strlen(str));

strstr

 int offset;

   char * position;

   char * str = "The quick brown dog jumps over the lazy fox";

   char * search_str = "dog";

         //返回搜索字符串'dog'在str中的第一个位置

   position = (char *)strstr(str, search_str);

   // strstr has returned the address. Now calculate * the offset from the beginning of str

         //按照内存中的相对位置计算offset量

   offset = (int)(position - str + 1);

   lr_output_message ("The string \"%s\" was found at position %d", search_str, offset);

strtok

extern char * strtok(char * string, const char * delimiters ); // Explicit declaration

   char path[] = "c:\\mercury\\lrun\\bin\\wlrun.exe";

         \\分隔符号为.或\

   char separators[] = ".\\";

   char * token;

   token = (char *)strtok(path, separators); //获取第一个token

   if (!token) {

       lr_output_message ("No tokens found in string!");

       return( -1 );

   }

   while (token != NULL ) {

                  //打印有效的token

       lr_output_message ("%s", token );

                  //获取下一个token，后续调用必须传递NULL作为字符串parameter.

       token = (char *)strtok(NULL, separators);

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