Basic operations of ordered storage structure linear tables are implemented in pure C Language

I wrote the sequence table in C language, tested it, made a question, and merged la and lb.

# Include <stdio. h> # include <stdlib. h> # define true 1 # define false 0 # define OK 1 # define error 0 # define Infeasible-1 # define overflow-2 # define list_inst_size 5 # define listincrement 1 typedef int status; typedef int elemtype; typedef struct {elemtype * ELEM; int length; int listsize;} SQL; static elemtype element;/* function name: initlist () parameter: SQL l initial condition: no function: Construct an empty linear table return value: Storage Allocation failed: overflow storage allocation successful: OK */status initlist (S QL & L) {If (L. ELEM = (elemtype *) malloc (sizeof (elemtype) * list_inst_size) = NULL) return overflow; else {L. length = 0; L. listsize = list_inst_size; Return OK ;}/ * function name: destroylist () parameter: SQL l initial condition: Linear table L existing function: Destroy linear table return value: l. ELEM = NULL: Error L. ELEM! = NULL: OK */status destroylist (SQL & L) {If (L. ELEM = NULL) Return Error; else {free (L. ELEM); Return OK;}/* function name: clearlist () parameter: SQL L; initial condition: Linear existing table l function: clear linear table return value: l. ELEM = NULL: Error L. ELEM! = NULL: OK */status clearlist (SQL & L) {If (L. ELEM = NULL) Return Error; else {L. length = 0; Return OK;}/* function name: listempty () parameter: SQL L; initial condition: Linear table function: determines whether the linear table is empty. Return: NULL: true non-null: false */status listempty (SQL & L) {If (L. length = 0) return true; else return false;}/* function name: listlength () parameter: SQL l initial condition: a linear table already exists function: return the return value of the linear table length: linear table length (L. length) */status listlength (SQL & L) {return L. length;}/* function name: getelem () parameter: sqlis T l, int I, elemtype * E (the global variable element is used here) initial condition: a linear table already exists. function: use e to return the return value of element I in a linear table: (I <1) | (I> listlength (L): overflow 1 <= I <= listlength (l): OK */status getelem (SQL & L, int I, elemtype & E) {If (I <1) | (I> listlength (L) return overflow; Int J; elemtype * P; P = L. ELEM; For (j = 0; j <I-1; j ++) L. ELEM ++; E = * L. ELEM; L. ELEM = P; Return OK;}/* function name: locateelem () parameter: SQL L, elemtype element initial condition: Linear Table l already exists. function: return the returned values of the first element equal to the element in the sequence table. If l contains an element equal to the element, returns the first element that meets the condition. If no element exists, returns 0 */status locateelem (SQL & L, elemtype e) {int I; elemtype * P; P = L. ELEM; for (I = 1; I <= L. length; I ++) {If (* L. ELEM = e) {L. ELEM = P; return I;} l. ELEM ++;} l. ELEM = P; return 0;}/* function name: priorelem () parameter: SQL L, elemtype cur_e, elemtype * pre_e initial condition: the linear table already exists, i> 1 & I <= L. length, locationelem () function: Use pre_e to return the precursor of cur_e in a linear table Returned value: I <= 1 | I> L. length: Overflow I> 1 & I <= L. length: OK */status priorelem (SQL & L, elemtype cur_e, elemtype * pre_e) {elemtype * P = L. ELEM; int I; I = locateelem (L, cur_e); // Why not use & L because it is called by reference if (I = 0) return overflow; Int J; for (j = 0; j <I-2; j ++) {L. ELEM ++;} * pre_e = * L. ELEM; // note that pre_e = L. ELEM does not work l. ELEM = P; Return OK;}/* function name: listinsert (); parameter: SQL l, int I, elemtype e initial condition: Linear table l already exists, 1 <= I <= L. length + 1; function: insert E before the I element of a linear table. Return Value: Failed: Error successful: OK */status listinsert (SQL & L, int I, elemtype E) {int * q = & (L. ELEM [I-1]); elemtype * newbase, * P; if (I <1 | I> (L. length) + 1) Return Error; If (L. length> = L. listsize) {newbase = (elemtype *) realloc (L. ELEM, L. listsize + listincrement * sizeof (elemtype); If (newbase = NULL) Exit (overflow); L. ELEM = newbase; L. listsize + = listincrement;} For (P = & (L. ELEM [L. length-1]); P> = Q; p --) * (p + 1) = * P; * q = E; ++ L. length; Return OK;}/* function name: listdelete () parameter: SQL l, int I; elemtype * E; initial condition: Linear table l already exists. 1 <= I <= L. length function: Delete the I-th element in a linear table, and return the value of the deleted number with E. Return Value: Failed: Error success: OK */status listdelete (SQL & L, int I, elemtype & E) {If (I <1) | (I> L. length) Return Error; E = (L. ELEM [I-1]); elemtype * q; For (q = & (L. ELEM [I-1]); q <& (L. ELEM [L. length-1]); q ++) {* q = * (q + 1);} l. length --; Return OK;} status listsee (SQL & L) {If (L. ELEM = NULL) | (L. length = 0) Return Error; else {int I; for (I = 0; I <L. Length; I ++) {printf ("% d", L. ELEM [I]);} printf ("\ n");} Return OK;} status listscan (SQL & L) {int I, A; printf ("Enter numbers: "); for (I = 0; I <list_inst_size; I ++) {scanf (" % d ", & A); listinsert (L, L. length + 1, A) ;}} int main () {SQL la, Lb; int I, e; initlist (LA); initlist (LB); listscan (LA ); listscan (LB); for (I = 0; I <lb. length; I ++) {e = LB. ELEM [I]; If (! Locateelem (La, E) listinsert (La, la. length + 1, e); // lb. ELEM ++;} printf ("La ="); listsee (LA); System ("pause"); Return 0 ;}