revert C-string without temp

revert.cpp

#include <string.h>
#include <stdio.h>

/*
	revert buffer C-string without temp
	abc\0 -> cba\0
	@str buffer
	@len size of buffer
*/
void revert(char* str, int len ){	
	for( int i = 0, e = len - 2; i < e; ++i, --e ){		
		*(str + i) ^= *(str + e);
		*(str + e) ^= *(str + i);
		*(str + i) ^= *(str + e);	
	}
}

int main(int argc, char const *argv[])
{
	char testString[] = "Test string";
	int len = sizeof(testString)/sizeof(char);
	
	char* str = new char[len];
	strcpy(str, testString);	
		
	printf("%s\n", str);
	revert(str, len);
	printf("%s\n", str);
	
	delete [] str;
	return 0;
}

g++ -Wall -pedantic -O3 -o exch revert.cpp && revert