#include<iostream>
using namespace std;
char * Myitoa(int a) {
char asign;
char temp[12];
char result[1024];
int last,one,i=0,j=0;
if(a<0)
{asign='-';
a=-a;
// cout<<a;
}
last=a;
while(last!=0){
one=last%10;
temp[i++]=one+'0';
last/=10;
//cout<<last<<endl;
}
if(asign=='-')
temp[i++]='-';
temp[i]='\0';
i--;
while(i>=0)
result[j++]=temp[i--];
result[j]='\0';
return result;
}
int Myatoi(char * str){
int asign=1,result=0;
if(str==NULL)
{ cout<<"invalue input"<<endl;
return -1;}
if(*str==' '||*str==' ')
str++;
if(*str=='-')
asign=-1;
if(*str=='-'||*str=='+')
str++;
while(*str!='\0'){
result=result*10+(*str-'0');
str++;}
return asign*result;
}
void * Mymemcpy(void * dest,void * str,size_t count){
char* pdest=static_cast<char *>(dest);
char* pstr=static_cast<char *>(str);
int a=0;
if(pdest>pstr&&pdest<pstr+count)
for(a=count-1;a!=-1;a--)
*(pdest+a)=*(pstr+a);
else
for(a=0;a<count;a++)
*(pdest+a)=*(pstr+a);
return pdest;
}
int main(){
int a=-1234;
//cout<<Myitoa(a)<<endl;
char *str="1234";
char * dest="2345";
cout<<Mymemcpy(dest,str,3)<<endl;
}