/in/ex7.c:7:1: error: unknown type name 'node_t'
node_t *Initialize(char ch) {//initialize
^
/in/ex7.c:8:5: error: use of undeclared identifier 'node_t'
    node_t *head;
    ^
/in/ex7.c:8:13: error: use of undeclared identifier 'head'; did you mean 'fread'?
    node_t *head;
            ^~~~
            fread
/usr/include/stdio.h:646:15: note: 'fread' declared here
extern size_t fread (void *__restrict __ptr, size_t __size,
              ^
/in/ex7.c:9:5: error: use of undeclared identifier 'head'
    head = (node_t *) calloc(1, sizeof(node_t));
    ^
/in/ex7.c:9:21: error: expected expression
    head = (node_t *) calloc(1, sizeof(node_t));
                    ^
/in/ex7.c:9:13: error: use of undeclared identifier 'node_t'
    head = (node_t *) calloc(1, sizeof(node_t));
            ^
/in/ex7.c:10:9: error: use of undeclared identifier 'head'; did you mean 'fread'?
    if (head == NULL) {
        ^~~~
        fread
/usr/include/stdio.h:646:15: note: 'fread' declared here
extern size_t fread (void *__restrict __ptr, size_t __size,
              ^
/in/ex7.c:10:9: error: comparison of function 'fread' equal to a null pointer is always false [-Werror,-Wtautological-pointer-compare]
    if (head == NULL) {
        ^~~~    ~~~~
/in/ex7.c:10:9: note: prefix with the address-of operator to silence this warning
    if (head == NULL) {
        ^
        &
/in/ex7.c:14:5: error: use of undeclared identifier 'head'
    head->next = NULL;
    ^
/in/ex7.c:15:5: error: use of undeclared identifier 'head'
    head->ch = ch;
    ^
/in/ex7.c:16:12: error: use of undeclared identifier 'head'; did you mean 'fread'?
    return head;
           ^~~~
           fread
/usr/include/stdio.h:646:15: note: 'fread' declared here
extern size_t fread (void *__restrict __ptr, size_t __size,
              ^
/in/ex7.c:19:16: error: unknown type name 'node_t'
void PrintList(node_t *head) {
               ^
/in/ex7.c:20:5: error: use of undeclared identifier 'node_t'
    node_t *temp = head;
    ^
/in/ex7.c:20:13: error: use of undeclared identifier 'temp'
    node_t *temp = head;
            ^
/in/ex7.c:22:12: error: use of undeclared identifier 'temp'
    while (temp != NULL) {
           ^
/in/ex7.c:23:23: error: use of undeclared identifier 'temp'
        printf("%c ", temp->ch);
                      ^
/in/ex7.c:24:9: error: use of undeclared identifier 'temp'
        temp = temp->next;
        ^
/in/ex7.c:24:16: error: use of undeclared identifier 'temp'
        temp = temp->next;
               ^
/in/ex7.c:29:15: error: unknown type name 'node_t'
void FreeList(node_t **head) {
              ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.