Implementation of Static Linked List ( in C/C++ )

Using static linked list is an alternative solution when the programming language you are using does not support

pointer operations. This short article gives some key operations of the static linked list.

 

// enum status_code { ... } #define MAX_SIZE 1000 #define N 100 typedef char ElemType[N]; struct component { ElemType data; int cur; }; typedef component SLinkList[MAX_SIZE]; int cell_malloc( SLinkList space ) { int i = space[0].cur; if( i != 0 ) space[0].cur = space[i].cur; else i = -1; return i; } void cell_free( SLinkList space, int k ) { space[k].cur = space[0].cur; strcpy( space[k].data, "FREE" ); space[0].cur = k; } void init_list( SLinkList lst ) { lst[MAX_SIZE - 1].cur = NULL; strcpy( lst[MAX_SIZE - 1].data, "Head" ); for( int i = 0; i < MAX_SIZE - 2; ++i ) { lst[i].cur = i + 1; strcpy( lst[i].data, "FREE" ); } lst[MAX_SIZE - 2].cur = NULL; strcpy( lst[MAX_SIZE - 2].data, "FREE" ); strcpy( lst[0].data, "Store" ); } void clear_list( SLinkList lst ) { int j = MAX_SIZE - 1, i = lst[j].cur; while( i != 0 ) { // delete lst[j].cur = lst[i].cur; // collect lst[i].cur = lst[0].cur; strcpy( lst[i].data, "FREE" ); lst[0].cur = i; i = lst[j].cur; } lst[MAX_SIZE - 1].cur = 0; } bool list_empty( SLinkList lst ) { return lst[MAX_SIZE - 1].cur == 0; } int list_size( SLinkList lst ) { int size = 0; int i = lst[MAX_SIZE - 1].cur; while( i != 0 ) { ++size; i = lst[i].cur; } return size; } status_code set_elem( SLinkList lst, int i, ElemType e ) { int j, k = 1; j = lst[MAX_SIZE - 1].cur; while( j != 0 && k < i ) { j = lst[j].cur; ++k; } if( j == 0 || k > j ) { printf( "Out of Range./n" ); return RangeError; } strcpy( lst[j].data, e ); return Success; } status_code get_elem( SLinkList lst, int i, ElemType & e ) { int j = lst[MAX_SIZE - 1].cur, k = 1; while( j != 0 && k < i ) { j = lst[j].cur; ++k; } if( j == 0 || k > i ) { return RangeError; } strcpy( e, lst[j].data ); return Success; } int locate_elem( SLinkList lst, ElemType e ) { int i = lst[MAX_SIZE - 1].cur; while( i != 0 && strcmp( lst[i].data, e ) != 0 ) i = lst[i].cur; return i == 0 ? -1 : i; } status_code prior_elem( SLinkList lst, ElemType e, ElemType & pre_e ) { int idx_pre = MAX_SIZE - 1, i = lst[idx_pre].cur; while( i != 0 && strcmp( lst[i].data, e ) != 0 ) { idx_pre = i; i = lst[i].cur; } if( i == 0 || idx_pre == MAX_SIZE - 1 ) return RangeError; strcpy( pre_e, lst[idx_pre].data ); return Success; } status_code next_elem( SLinkList lst, ElemType e, ElemType & next_e ) { int i = lst[MAX_SIZE - 1].cur; while( i != 0 && strcmp( lst[i].data, e ) != 0 ) i = lst[i].cur; if( i == 0 || lst[i].cur == 0 ) return RangeError; i = lst[i].cur; strcpy( next_e, lst[i].data ); return Success; } status_code list_insert( SLinkList lst, int i, ElemType e ) { status_code res = Success; int j = 0, k = MAX_SIZE - 1; while( lst[k].cur != 0 && j < i - 1 ) { ++j; k = lst[k].cur; } if( i == 0 || j > i - 1 ) return RangeError; int l = cell_malloc( lst ); if( l != -1 ) { strcpy( lst[l].data, e ); lst[l].cur = lst[k].cur; lst[k].cur = l; } else res = RangeError; return res; } status_code list_delete( SLinkList lst, int i, ElemType & e ) { int k = MAX_SIZE - 1; while( k != 0 && lst[k].cur != i ) { k = lst[k].cur; } if( lst[k].cur == 0 ) return RangeError; strcpy( e, lst[i].data ); lst[k].cur = lst[i].cur; cell_free( lst, i ); return Success; } void list_traverse( SLinkList lst ) { int i = lst[MAX_SIZE - 1].cur; while( i != 0 ) { printf( "%s ", lst[i].data ); i = lst[i].cur; } printf( "/n" ); } void print( SLinkList lst ) { for( int i = 0; i < MAX_SIZE; ++i ) printf( "%d/t%s/t%d/n", i, lst[i].data, lst[i].cur ); printf( "/n" ); } void symm_diff( SLinkList & space, int & h ) { init_list( space ); h = MAX_SIZE - 1; int len_a = 4, len_b = 3; char str[10]; printf( "Input Elements of A (%d):/n", len_a ); while( len_a-- ) { scanf( "%s", str ); list_insert( space, 1, str ); print( space ); } printf( "Input Elements of B (%d):/n", len_b ); while( len_b-- ) { scanf( "%s", str ); int pos = locate_elem( space, str ); if( pos == -1 ) list_insert( space, 1, str ); else list_delete( space, pos, str ); printf( "After %s was deleted./n", str ); print( space ); } }