#include<stdlib.h>
char input[6] = {'a','b','c','d','e','f'};
void reverseAll(char* input, int start, int end){
char temp;
while(start < end){
temp = input[start];
input[start] = input[end];
input[end] = temp;
start++;
end--;
}
}
void reverse(char* input, int len, int k){
reverseAll(input, 0, len - 1);
reverseAll(input, 0, k-1);
reverseAll(input, k, len - 1);
}