int main()
{
	char tekst[20];
 
	cout<< "Put in a line of text! ";
 
	cin.getline(tekst, 20);
 
	cout<< "Reverse the string now!" <<endl;
 
	for (int i=0; i<sizeof tekst; i++)
		cout<< tekst [sizeof tekst-i-1];
 
	cout<<endl;
	return 0;
}

int Reverse(char* str)
{
 
if (NULL==str)return -1; //no string
int l=strlen(str)-1; //get the string length
if (1==l)return 1;
 
for(int x=0;x < l;x++,l--)
{
str[x]^=str[l];  //triple XOR Trick
str[l]^=str[x];  //for not using a temp
str[x]^=str[l];
}
 
return 0;
 
}

#include <algorithm>
#include <cstring>
#include <iostream>
 
using namespace std;
 
void sreverse(char *s)
{
  size_t begin = 0;
  size_t end = strlen(s) - 1;
 
  while (begin < end)
    swap(s[begin++], s[end--]);
}
 
int main()
{
  char s[20];
 
  cout<<"Enter a string: ";
  if (cin.getline(s, sizeof s)) {
    sreverse(s);
    cout<< s <<endl;
  }
}

#include <cstring>
#include <iostream>
 
using namespace std;
 
int main()
{
  char s[20];
 
  cout<<"Enter a string: ";
  if (cin.getline(s, sizeof s)) {
    for (size_t i = strlen(s) - 1; i != 0; i--)
      cout<< s[i];
    cout<< s[0] <<endl;
  }
}

a ^= b ^= a ^= b;