Virtual implementation of string manipulation algorithm

String: It is a finite sequence of 0 or more characters in a finite character set//a special linear table int Indexz (string s,string t,int pos) {//t is a non-empty string, if there is a substring equal to T after the first POS character in the main string S, Returns the position of the first such substring in S if (pos>0) {n=strlength (S);//Find the length of the main string m=strlength (T);//Find out the length of a non-empty string I=pos;while (i<=n-m+1) { SubString (sub,s,i,m); if (Strcompare (sub,t)!=0)//Let non-empty string and main string compare equality i++;//if not, let non-empty string move on main string one Elsereturn i;//if found the same, Returns the position in the main string}}return 0;} 1. Define the length of the string # # # Maxstrlen 255//users can define the maximum string length typedef unsigned char sstring[maxstrlen+1];//0 number cell to store the lengths of the string//2. String Link: Returns a new string of links from S1 and S2 with T, if not truncated, returns Truestatus Concat (sstring &t,sstring s1,sstring S2) {if (S1[0]+s2[0]<=maxstrlen) If the sum of two string lengths is less than the length of the new string T {T[1...s1[0]=s1[1..s1[0]];//s1[0] represents the last element, assign all the elements in the S1 to T T[s1[0]+1..s1[0]+s2[0]]=s2[1...s2[0]] ;//The S2 element is assigned to the S1 element +1, just link t[0]=s1[0]+s2[0];//the last T string length is two string length and uncut=true;//is not truncated}else if (s1[0]<maxstrsize)// In the second case, the S1 length is less than T, but S1+S2 is greater than T, so that the S1 is fully inserted, and S2 does not fully {t[1..s1[0]=s1[1...s1[0]];//assigns the elements in S1 to T t[s1[0]+1...maxstrlen]=s2[1: maxstrlen-s1[0]];//to link some elements of S2 to S1 the length of the t[0]=maxstrlen;//t is equal to the allocation length of the start T uncut=false;//the string is truncated}else//The third case, the string T equals the length of the string S1. {t[0...maxstrlen]=s1[0...maxstrlen];//S1 all elements into T uncut=false;//be truncated}return Uncut;} 3. The function of the substring//returns the first POS character of the string s with a sub string of length Len//1<=pos<=strlength (s) and 0<=len<=strlength (s)-pos+1status SubString (sstring &sub,sstring s,int pos,int len) {if (pos<1| | pos>s[0]| | len<0| | LEN&GT;S[0]-POS+1)//If the POS is illegal or the length overflows, return error;//returns error Sub[1..len]=s[pos: pos+len-1];//assigns a substring of the matching condition to the new string sub[0]=len;//sub[0] to hold the length of the array return OK; 4. SUBSTRING matching algorithm. : Returns the position of the substring T after the POS character in the main string S,//If it does not exist, returns the 0{i=pos;//i pointer to the main string j=1;//j the pointer while (I&LT;=S[0]&AMP;&AMP;J&LT;=T[0])// If the two pointers are less than the respective maximum length {if (s[i]==t[j])//If the comparison is equal {i++;//let the main string pointer move to the next position j++;//the substring pointer moves to the next position}else{i=i-j+2;//backtracking, is to let the main string pointer back to the last comparison, the most starting point j=1;//let the substring to start from the beginning with the main string comparison}}if (J>t[0])//When the substring pointer moves to the end is still equal, then return to its position, indicating that find return I-t[0];elsereturn 0;} 5. String permutation: The "S" in the string "T" all the occurrences of the "V"//in S to locate T, and then according to the length of the T and V; T.curlen<v.curlen: After moving V.curlen-t.curlent.curlen=v.curlen : Replace T.curlen>v.curlen: Move forward t.curlen-v.curlen//repeat until T exists in s

Virtual implementation of string manipulation algorithm