[A good way to split strings by TAG] strtok function introduction and application.

Just getting started with the strtok function is amazing. Definition: strtok Syntax: # include <string. h> char * strtok (char * str1, const char * str2); Function. If the separator is not found, the function returns NULL. To convert a string into a tag, str1 is called for the first time as the tag separator. Therefore, all calls to str1 should be NULL. For example: [cpp] char str [] = "now # is the time for all # good men to come to the # aid of their country "; char delims [] = "#"; char * result = NULL; result = strtok (str, delims); while (result! = NULL) {printf ("result is \" % s \ "\ n", result); result = strtok (NULL, delims);} the result of this sample is: result is "now" result is "is the time for all" result is "good men to come to the" result is "aid of their country" implemented through '#' split purpose. Typical applications, such as HDU 1106: to open the question link, split the string by 5 and convert it to a string for sorting. The general method is direct simulation, but if you use the strtok function flexibly (note that its return value is a pointer) and the string is converted to the numeric function atoi (), this question is very simple. [Cpp] # include <iostream> # include <algorithm> # include <cstring> # include <string. h> # include <stdlib. h> using namespace std; bool cmp (int a, int B) {return a <B;} int num [1009]; int main () {char tar [1009]; while (cin> tar) {string numpack [1000]; memset (num, 0, sizeof (num); int pos = 0; int start = 0, end = 0; char * temp; temp = strtok (tar, "5"); // separate by 5 also while (temp! = NULL) {numpack [pos] = temp; temp = strtok (NULL, "5"); // basic usage: Save the pointer to the array pos ++ ;} for (int I = 0; I <pos; I ++) {num [I] = atoi (numpack [I]. c_str ();} sort (num, num + pos, cmp); for (int I = 0; I <pos; I ++) {cout <num [I]; if (I! = Pos-1) cout <"; else cout <endl ;}return 0 ;}