C replaceall Method

The replaceall method written by others is not very good on the Internet, so I feel that I have to write it myself because of the rush of time. If there is something wrong, please give me more advice.

The C code is as follows:

# Include <stdio. h> # include <malloc. h> # include <string. h> char * replaceall (char * SRC, char * Find, char * replacewith) {// If find or replace is null, return the same string as SRC. If (find = NULL | replacewith = NULL) {return strdup (SRC);} // point to the head of the replaced string. Char * afterreplacehead = NULL; // always points to the end of the new string. Char * afterreplaceindex = NULL; // The number of times the find string appears in the SRC string int COUNT = 0; int I, j, k; int srclen = strlen (SRC ); int findlen = strlen (FIND); int replacewithlen = strlen (replacewith); // point to a location of the SRC string, from which the substring is copied to afterreplaceindex, initially, the data is copied from the SRC head. Char * srcindex = SRC; // a subscript of the SRC string. From this subscript, copy the string to afterreplaceindex, which is the first character of SRC. Int cpstrstart = 0; // obtain the number of times the find string appears in the SRC string COUNT = getfindstrcount (SRC, find); // if it does not appear, return the same string as the SRC string. If (COUNT = 0) {return strdup (SRC) ;}// apply for memory afterreplacehead = afterreplaceindex = (char *) malloc (srclen + 1 + (replacewithlen-findlen) for the new string) * count); // initialize the new string memory memset (afterreplacehead, '\ 0', sizeof (afterreplacehead); for (I = 0, j = 0, K = 0; i! = Srclen; I ++) {// if the character of the find string is the same as that of the character string in SRC. If (SRC [I] = find [J]) {// If the comparison is just started, the I value is first assigned to K for saving. If (j = 0) {k = I;} // If the find string is contained in the SRC string if (j = (findLen-1) {J = 0; // copy the string before the find string in SRC to strncpy (afterreplaceindex, srcindex, I-findlen-cpstrstart + 1) in the new string ); // modify response = afterreplaceindex + I-findlen-cpstrstart + 1; // modify srcindexsrcindex = srcindex + I-findlen-cpstrstart + 1; // cpstrstartcpstrstart = I + 1; // copy the replacewith string to the new string strncpy (afterreplaceindex, replac Ewith, replacewithlen); // modify afterreplaceindexafterreplaceindex = afterreplaceindex + replacewithlen; // modify srcindexsrcindex = srcindex + findlen;} else {J ++ ;}} else {// If the find and SRC values are inconsistent during the comparison, return the saved K value to IIF (J! = 0) {I = K;} J = 0 ;}// Finally, copy the string following the last find matching string in SRC to the new string. Strncpy (afterreplaceindex, srcindex, I-cpstrstart); Return afterreplacehead;} int getfindstrcount (char * SRC, char * Find) {int COUNT = 0; char * position = SRC; int findlen = strlen (FIND); While (position = strstr (Position, find ))! = NULL) {count ++; position = Position + findlen;} return count ;}int main (void) {char * s = "12345345443344341334542345"; // call the function replaceall, S is the source string, "345" is the string to be replaced, and "7890" is the replacement string. Char * r = replaceall (S, "345", "7890"); printf ("% s \ n", R); // do not use the replaceall function, because replace contains the memory of the malloc result string. Free (r); Return 0 ;}

Running result:

127890789044334434137890427890