(盐城工学院数据结构课程设计)栈的应用表达式求值 下载本文

Stack Whereat; char sample;

InputFile = fopen(\ /*打开文件*/ OutputFile = fopen(\

Whereat = malloc(sizeof(struct Node)); /*给 Whereat分配空间*/ Whereat->Next = NULL; if (!Input !OutputFile) { /*错误处理*/ printf(\ return(1); }

sample = getc(InputFile); while ( sample != EOF){ Temp = fopen(\ /*生成Temp文件*/ ungetc(sample,InputFile); /* put back sample字符*/ ConvertToPost(Input); /*中缀变后缀*/ if (PrintError){ /*错误处理*/ fprintf(OutputFile,\ fscanf(InputFile,\ PrintError = 0;

} else if (IsEmpty(Whereat) == 1){ /*跳过在input文件中的空格*/ } else if (IsEmpty(Whereat) != 1){ Reverse(Whereat); if (Top(Whereat) == 'B'){ /*错误处理,*/ /*A表示操作数B表示运算符*/ PrintError = 1; /*后缀表达式第一个元素应是操作数而不是运算符号*/

} fclose(Temp); Temp = fopen(\ Calculate(OutputFile, Whereat,Temp); /*计算结果*/ } fclose(Temp); MakeEmpty(Whereat); /* 清空Whereat用来处理下一行*/ putc('\\n',OutputFile); /* 在输出文件中换行*/ sample = getc(InputFile);

} /* While循环结束*/

free(Whereat); fclose(InputFile); fclose(OutputFile);

remove(\ /* 删除Temp.txt*/ return 1; }

/******检查堆栈是否为空******/ int IsEmpty(Stack S) {

return(S->Next==NULL); }

/******检查float堆栈是否为空******/ int FIsEmpty(FStack S) {

return(S->Next==NULL); }

/******弹出栈顶元素******/ void Pop(Stack S) { }

PtrToNode FirstCell; if (IsEmpty(S)) perror(\ else{ FirstCell = S->Next; S->Next = S->Next->Next; free(FirstCell); }

/******弹出float栈顶元素******/ void FPop(FStack S) {

Ptr_Fn FirstCell; if (FIsEmpty(S)) perror(\ else{ FirstCell = S->Next; S->Next = S->Next->Next; free(FirstCell);

} }

/******将堆栈置空******/ void MakeEmpty(Stack S) {

if (S == NULL) perror(\ else while (!IsEmpty(S)) Pop(S); }

/******将float堆栈置空******/ void FMakeEmpty(FStack S) {

if (S == NULL) perror(\ else while (!IsEmpty(S)) Pop(S); }

/******元素进栈******/ void Push(char X, Stack S) {

PtrToNode TmpCell;

TmpCell = (PtrToNode)malloc(sizeof(struct Node)); if (TmpCell == NULL) perror(\ else{

TmpCell->Element = X; TmpCell->Next = S->Next; S->Next = TmpCell; } }

/******float元素进栈******/ void FPush(float X, FStack S) {

Ptr_Fn TmpCell;

TmpCell = (Ptr_Fn)malloc(sizeof(struct FNode));

if (TmpCell == NULL) perror(\ else{ TmpCell->Element = X; TmpCell->Next = S->Next; S->Next = TmpCell; } }

/******返回栈顶元素******/ char Top(Stack S)

{

if (!IsEmpty(S)) return S->Next->Element; perror(\ exit(1); return 0; }

/******返回float栈顶元素******/ float FTop(FStack S)

{

if (!FIsEmpty(S)) return S->Next->Element; perror(\ exit(1); return 0; }

/******将堆栈元素倒置******/ void Reverse(Stack Rev) { }

Stack Tempstack;

Tempstack = malloc(sizeof(struct Node)); Tempstack->Next = NULL; while (!IsEmpty(Rev)){ Push(Top(Rev),Tempstack); /*将元素压栈到一个临时堆栈*/ Pop(Rev); } Rev->Next = Tempstack->Next; /*指向新的堆栈*/