#include <iostream>
#include <string>
using namespace std;
void main()
{
string s1,s2;
cout<<"Nhap chuoi 1: ";
cin >> s1;
cout<<"Xuat chuoi 2:";
cin >> s2;
//cout<<"Do dai cua chuoi : "<<s1<<s2<<"\n";
int kq1,kq2,kq;
kq1 = s1.length();
kq2 = s2.length();
kq=kq1+kq2;
cout<<kq<<"\n";
if (kq1>kq2 || kq1==kq2)
{
int i;
for (i=0;i<kq1-1;i++)
{
cout<<s1.at(i)<<".";
}
cout<<s1.at(i)<<"\n";
}
else
{
int j;
for(j=0;j<kq2-1;j++)
{
cout<<s2.at(j)<<".";
}
cout<<s2.at(j)<<"\n";
}
if(kq1<kq2)
{
cout<<"-1";
}
else
if(kq1==kq2)
{
cout<<"0"<<"\n";
}
else cout<<"1"<<"\n";
if(kq1>kq2)
{
s2=s1;
cout<<s2<<"\n";
}
// Bat dau tu day la Thay lam nha .
if (a.compare(b)== 1)
{
t = a;
a = b;
b = t;
}
cout <<"a="<<a<<"\n";
cout <<"b="<<b<<"\n";
string c = a;
c.append(b);
cout <<"c="<<c<<"\n";
string d = c.substr(a.length(),b.length());
cout <<"d="<<d<<"\n";
if(b.compare(d) == 0)
{
cout <<"Dung roi !"<<"\n";
}
else {
cout <<"Sai roi !"<<"\n";
}
cout<<"a xuat hien trong c tai : "<<c.find(a)<<"\n";
cout<<"b xuat hien trong c tai : "<<c.find(b)<<"\n";
cout<<"d xuat hien trong c tai : "<<c.find(d)<<"\n";
c.insert(c.find(b),d);
cout<<"c="<<c<<"\n";
}
Tiêu đề: code tuần 4 LTHDT 
