CareerCup

char str[] = "killerX";
int n;
int i;
n = strlen(str);
for(i=0;i<n/2;i++)
swap(str[i], str[n-1-i]);

Iterate through [length]/2 and swap char at front (i) with char at back (length-1-i).

Iterate through [length]/2 and swap char at front (i) with char at back (length-1-i).

char string[] = "Hello World";
char* start = char* end = string;
end += strlen(string) - 1;

while(start<end)
{
*start = *end;
start++;
end--;
}

above prg over writing "Hello" with "world", use temp variable to swap chars

"Hello" with "dlrow"

swap without temp var

char A, B;
A = A xor B;
B = A xor B;
A = A xor B;

Use
Arrays.sort(arrayElement,Collections.reverseOrder()); // arrayElement is the array passed as input.