本文共 3222 字，大约阅读时间需要 10 分钟。
#include#include #include typedef struct Mystack *Stack;struct Mystack { int Capacity; /* 栈的容量 */ int Top_of_stack; /* 栈顶下标 */ char *Array; /* 存放栈中元素的数组 */};/* 栈的创建 */Stack CreateStack(int Max){ Stack S; S = malloc(sizeof(struct Mystack)); if (S == NULL) printf("Create stack error!\n"); S->Array = malloc(sizeof(char) * Max); if (S->Array == NULL) printf("Create stack error!\n"); S->Capacity = Max; S->Top_of_stack = 0; return S;}/* 释放栈 */void DisposeStack(Stack S){ if (S != NULL) { free(S->Array); free(S); } }/* 判断一个栈是否是空栈 */int IsEmpty(Stack S){ return !S->Top_of_stack;}/* 判断一个栈是否满栈 */int IsFull(Stack S){ if (S->Top_of_stack == S->Capacity - 1) return 1; else return 0;}/* 数据入栈 */int Push(int x, Stack S){ if (IsFull(S)) printf("The Stack is full!\n"); else S->Array[S->Top_of_stack++] = x;}/* 数据出栈 */int Pop(Stack S){ if (IsEmpty(S)) printf("The Stack is empty!\n"); else S->Top_of_stack--;}/* 将栈顶返回 */char Top(Stack S){ if (!IsEmpty(S)) return S->Array[S->Top_of_stack-1]; printf("The Stack is empty!\n"); return 0;}/* 计算优先级 */int getPriority(char a){ switch(a) { case '#': return 0; break; case '+': case '-': return 1; break; case '*': case '/': return 2; break; case '(': return 3; break; default: break; }}int main(){ int i, len; char str[100]; printf("Please input the Infix expression that you want to change: \n"); scanf("%s", str); len = strlen(str); /* 根据序列的长度来创建栈 */ struct Mystack *my_stack = CreateStack(len+1); /* 利用‘#’是为了第一进栈时能方便统一的进行判断 */ Push('#', my_stack); for (i = 0; i < len; i++) { if ((str[i] >= '0' && str[i] <= '9') || (str[i] >= 'a' && str[i] <= 'z')) /* 操作数 */ { printf("%c", str[i]); } else if (str[i] != ')' && getPriority(str[i]) > getPriority(Top(my_stack))) /* 当栈顶元素优先级比下一个操作符优先级小时，把外面的操作符直接进栈 */ { Push(str[i], my_stack); } else if (str[i] != ')' && getPriority(str[i]) <= getPriority(Top(my_stack)))/* 栈顶元素优先级大于等于下一个操作符的优先级，这时要出栈，但要确保'('不出栈 */ { while(getPriority(str[i]) <= getPriority(Top(my_stack)) && Top(my_stack) != '(' ) { printf("%c", Top(my_stack)); Pop(my_stack); } Push(str[i], my_stack); } else if (str[i] == ')') /* 如果遇见一个右括号，那么就将栈顶元素弹出，直至遇见一个左括号为止 */ { while (Top(my_stack) != '(') { printf("%c", Top(my_stack)); Pop(my_stack); } Pop(my_stack); } } /* 输出栈中剩余的元素 */ if (!IsEmpty(my_stack)) { while (Top(my_stack) != '#') { printf("%c", Top(my_stack)); Pop(my_stack); } printf("\n"); } DisposeStack(my_stack); return 0;}
测试数据：
shang@shang:~/C$ ./a.outPlease input the Infix expression that you want to change:a+b*c+(d*e+f)*gabc*+de*f+g*+
转载地址：http://uphvb.baihongyu.com/