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

//	Function to reverse portion of string from position 'start' to 'end'.
void reverseString(char* str, int start, int end) {
  int i, len = (end - start) + 1;
  for (i = 0, str = str + start; i < len / 2; i++) {
    char temp = *(str + i);
    *(str + i) = *(str + len - 1 - i);
    *(str + len - 1 - i) = temp;
  }
}

void main() {
  char str[20], revStr[20];
  int start, end;

  printf("Enter a string: ");
  fgets(str, sizeof(str), stdin);
  strcpy(revStr, str);

  printf("Enter start and end positions: ");
  scanf("%d %d", &start, &end);
  reverseString(str, start, end);
  printf("\nReverse of portion of the sentence:");
  printf("\n%s\n", str);

  printf("\nReverse of entire sentence:");
  reverseString(revStr, 0, strlen(revStr) - 1);
  printf("\n%s", revStr);
}