Робота с строками в С++

char*str1;
cout<<"\nvvedit 1\n";
cin>>str1;
int i2=strlen(str1);
cout<<i2;
 
for (int i = i2; i>=0; i--)
{
cout<<str1[i];
}

char*str1;
cout<<"\nvvedit 1\n";
cin>>str1;
int i2=strlen(str1);
cout<<i2;
 
for (int i = i2-1; i>=0; i--)
{
cout<<str1[i];
}

char* str1;
cout<<"\nvvedit 1\n";
cin>>str1;
int i2=strlen(str1);
cout<<i2;
 
for (int i = 0; i < i2 / 2; i++){
  char tmp = str1[i];
  str1[i] = str1[i2 - i - 1];
  str1[i2 - i - 1] = tmp;
}
 
cout << str1 << endl;

#include <iostream>
#include <cstring>
 
int main()
{
  const int  max_lenght = 256;
        char string[max_lenght];
 
 
  std::cout << "Enter string: ";
  std::cin.getline(string, max_lenght);
 
  int lenght = static_cast<int>(std::strlen(string));
 
  for (int i = 0; i < lenght / 2; ++i){
    char tmp               = string[i];
    string[i]              = string[lenght - i - 1];
    string[lenght - i - 1] = tmp;
  }
 
  std::cout << string << std::endl;
 
  return 0;
}

#include <iostream.h>
#include <string.h>
#include <conio.h>
 
main()
{
 string str;
 cout<<"Input data:\n";
 cin>>str;
 
 int len=str.length()-1;
   for (int i = len; i>=0; i--)
     {
       cout<<str[i];
     }
 
     char*str1;
     cout<<"\nInput (char) data:\n";
     cin>>str1;
     int i2=strlen(str1);
     cout<<"Lenght = "<<i2<<"\n";
 
        for (int i = i2; i>=0; i--)
         {
           cout<<str1[i];
         }
 
   getch();
}

#include <iostream.h>
#include <string.h>
#include <conio.h>
 
main()
{
 
char*str1;
cout<<"\nInput (char) data:\n";
cin>>str1;
int i2=strlen(str1);
cout<<"Lenght = "<<i2<<"\n";
 
for (int i = i2; i>=0; i--)
{
cout<<str1[i];
}
 
getch();
}

#include <iostream.h>
#include <string.h>
#include <conio.h>
 
main()
{
 
char str1[260];
cout<<"\nInput (char) data:\n";
cin>>str1;
int i2=strlen(str1);
cout<<"Lenght = "<<i2<<"\n";
 
for (int i = i2; i>=0; i--)
{
cout<<str1[i];
}
 
getch();
}

#include <algorithm>
#include <string>
#define ALL(a) a.begin(), a.end()
//--------------
string s;
//--------------
reverse(ALL(s));