stackli.h
1 /* 栈的链表实现的类型声明*/ 2 3 typedef int ElementType; 4 /* START: fig3_39.txt */ 5 #ifndef _Stack_h 6 #define _Stack_h 7 8 struct Node; 9 typedef struct Node *PtrToNode; 10 typedef PtrToNode Stack; 11 12 int IsEmpty( Stack S ); 13 Stack CreateStack( void ); 14 void DisposeStack( Stack S ); 15 void MakeEmpty( Stack S ); 16 void Push( ElementType X, Stack S ); 17 ElementType Top( Stack S ); 18 void Pop( Stack S ); 19 20 #endif /* _Stack_h */ 21 22 /* END */
stackli.c
1 #include "stackli.h" 2 #include "fatal.h" 3 #include <stdlib.h> 4 5 struct Node 6 { 7 ElementType Element; 8 PtrToNode Next; 9 }; 10 11 /* START: fig3_40.txt */ 12 13 /* 判断栈是否为空 */ 14 int 15 IsEmpty( Stack S ) 16 { 17 return S->Next == NULL; 18 } 19 /* END */ 20 21 /* START: fig3_41.txt */ 22 23 /* 创建一个空栈 */ 24 Stack 25 CreateStack( void ) 26 { 27 Stack S; 28 29 S = malloc( sizeof( struct Node ) ); 30 if( S == NULL ) 31 FatalError( "Out of space!!!" ); 32 S->Next = NULL; 33 MakeEmpty( S ); 34 return S; 35 } 36 37 /* 使栈为空 */ 38 void 39 MakeEmpty( Stack S ) 40 { 41 if( S == NULL ) 42 Error( "Must use CreateStack first" ); 43 else 44 while( !IsEmpty( S ) ) 45 Pop( S ); 46 } 47 /* END */ 48 49 /* 释放栈 */ 50 void 51 DisposeStack( Stack S ) 52 { 53 MakeEmpty( S ); 54 free( S ); 55 } 56 57 /* START: fig3_42.txt */ 58 59 /* 入栈 */ 60 void 61 Push( ElementType X, Stack S ) 62 { 63 PtrToNode TmpCell; 64 65 TmpCell = malloc( sizeof( struct Node ) ); 66 if( TmpCell == NULL ) 67 FatalError( "Out of space!!!" ); 68 else 69 { 70 TmpCell->Element = X; 71 TmpCell->Next = S->Next; 72 S->Next = TmpCell; 73 } 74 } 75 /* 76 有头节点，栈顶是第一个节点，入栈是插到第一个节点前面，变成第一个节点 77 这样出栈方便 78 */ 79 80 /* END */ 81 82 /* START: fig3_43.txt */ 83 84 /* 返回栈顶元素 */ 85 ElementType 86 Top( Stack S ) 87 { 88 if( !IsEmpty( S ) ) 89 return S->Next->Element; 90 Error( "Empty stack" ); 91 return 0; /* Return value used to avoid warning */ 92 } 93 /* END */ 94 95 /* START: fig3_44.txt */ 96 97 /* 出栈 */ 98 void 99 Pop( Stack S ) 100 { 101 PtrToNode FirstCell; 102 103 if( IsEmpty( S ) ) 104 Error( "Empty stack" ); 105 else 106 { 107 FirstCell = S->Next; 108 S->Next = S->Next->Next; 109 free( FirstCell ); 110 } 111 } 112 /* END */