SML Programming Question Write a function flip to flip int * int list. One function only.  flip[(2,~3),(5,4)] > [(~3,2),(4,5)]

Write a function sum_alt that takes a list of numbers zand calculates their alternating sum, defined as n-1 Σ(-1)+1 zk. k=0 Here Zo, Z1, Zn-1 denote the individual elements of the list.

in #lang scheme

Write a user defined function named as “length_list” function that finds the length of a list of list_node_t nodes. This code should fit with the following code.Partial Code: #include <stdio.h> #include <stdlib.h> /* gives access to malloc */ #define SENT -1 typedef struct list_node_s { int digit; struct list_node_s *restp; } list_node_t; list_node_t *get_list(void); int main(void) { list_node_t *x;int y; x=get_list(); printf("%d\n",x->digit); printf("%d\n",x->restp->digit); printf("%d\n",x->restp->restp->digit); // your length_list function should be called from here printf("Length is: %d",y); } /* * Forms a linked list of an input list of integers * terminated by SENT */ list_node_t * get_list(void) { int data; list_node_t *ansp; [20]scanf("%d", &data); if (data == SENT) { ansp = NULL; } else { ansp = (list_node_t *)malloc(sizeof (list_node_t)); ansp->digit = data; ansp->restp = get_list(); } return (ansp);