Reversing the sequence of a string [closed] - c++

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A fairly simple program, trying to reverse the characters in a null terminated string in C++, but something seems to be going wrong.
#include <iostream>
using namespace std;
void reverse(char*);
int main(){
char *str;
cout<< "Please enter a string, no spaces please..";
cin >> str;
//reverse(str);
}
void reverse(char *str){
char temp;
size_t len = strlen(str);
for (size_t i = 0; i < len/2; i--)
{
temp = str[i];
str[i] = str[len-i-1];
str[len-i-1] = temp;
}
}
Getting the following error
Bus error: 10
Any help appreciated.

Answer 1

Allocate memory for str before use char *str = new char[25];
In reverse function for for loop increment i for (size_t i = 0; i < len/2; i++ )
Deallocate memory after use delete [] str ;

Answer 2

You are decrementing iterator i insted of incrementing it. A little bit compact version of yours:
#include <algorithm>
#include <cstring>
void reverse(char* const str)
{
unsigned long const len = strlen(str);
for(unsigned long i = 0; i < len >> 1; i++)
std::swap(str[len - i - 1], str[i]);
}

Answer 3

#include <algorithm>
#include <string>
#include <iostream>
#include <cstring>
int main() {
// You can't read something to nowhere.
// String will be holded in static array.
char str[1024];
// To keep it as null terminated string after
// writing of inputed string: `std::cin` don't
// write null character after writing of data.
memset(str, 0, 1024);
std::cin >> str;
// If you do reversing of strings in C++,
// you shouldn't use hand written loops:
std::reverse(str, str + strlen(str));
std::cout << str << std::endl;
}

Answer 4

Try this modified version of your code:
#include <iostream>
#include <cstring>
using namespace std;
void reverse(char*);
int main(){
char str[1024]; // buffer of 1024 chars
cout<< "Please enter a string, no spaces please..";
cin >> str;
reverse(str);
cout << "\nReversed: " << str;
}
void reverse(char *str){
char temp;
size_t len = strlen(str);
for (size_t i = 0; i < len/2; i++) // loop until half of the user input
{
temp = str[i];
str[i] = str[len-i-1];
str[len-i-1] = temp;
}
}
I simply added the array of char char str[1024]; to store the user input.. and changed the loop to: for (size_t i = 0; i < len/2; i++)
However, you must be very careful with the above code.. it works properly if the size of the input is less than the array fixed size.