**The prototype **Extern char *strcat(char *dest,char * SRC); **usage **# include < String. H > **function **Add the SRC reference string to the end of dest (overwriting the ‘\0’ at the end of dest) and add ‘\0’. **instructions **The memory area indicated by SRC and dest must not overlap and dest must have enough space to hold the SRC string. Returns a pointer to dest. **For example, **  Char str4[] = “Hello world”;   Char str5[] = “Hello World”;   cout < < Strcat (str4 str5) < < Endl; It’s going to go wrong because str4 doesn’t have enough space The following is an implementation of my own, shortcomings, also hope to correct!!

#include "stdafx.h"
#include <iostream>
#include <assert.h>
using namespace std;
//Concatenation string
char* mystrcat(char* destStr,const char* srcStr)  //What if two strings are the same string?
{
 assert(destStr != NULL && srcStr != NULL);
 char* temp=destStr;
 while(*destStr != '0')
 {
  ++destStr;
 }
 while(*destStr++ = *srcStr++)
  NULL;
 return temp; //To implement the chain operation, the destination address is returned
}
int _tmain(int argc, _TCHAR* argv[])
{
 char str1[25] = "Hello world";
 char str2[] = "Hello World";
 cout << mystrcat(str1,str2) << endl;
 return 0;
}