计算器c语言代码中缀表达式,C语言简易计算器（中缀表达式转后缀表达式，通过堆栈实现）...
用C语言，写了一个简易的计算器，只有加减乘除，没有括号，但是若果要实现括号也是很容易的。
例如：输入中缀表达式2+2*3/2-1，程序可将其转换成后缀表达式2,2,3,2,/,*,+,1,- 其中','是为了间隔开数字，便于提取。最终的输出结果为：4
第一次发帖，本人菜鸟，欢迎高手批评指正！
代码如下：
#include "stdio.h"
#include "string.h"
#include "malloc.h"
typedef struct tag_STACK_STRU
{
float valueData;
struct tag_STACK_STRU *pNext;
}stackList;//用链表实现数据的存储
stackList *g_stOperand = NULL;//操作数
stackList *g_stOperator = NULL; //操作符
void makeEmpty(stackList *stack);//清空栈
char isEmpty(stackList *stack);//判断栈是否为空
void push(stackList *stack, float data);//入栈操作
void pop(stackList *stack);//出栈操作
void calculate(char *p);//计算的子程序
void changeStr(char *p);//将中缀表达式转换为后缀表达式
char suffixStr[1024];
int main()
{
// 业务代码实现处
char *p = (char *)malloc(sizeof(char));
g_stOperand = (stackList *)malloc(sizeof(stackList));
g_stOperand->pNext = NULL;
makeEmpty(g_stOperand);
g_stOperator = (stackList *)malloc(sizeof(stackList));
g_stOperator->pNext = NULL;
makeEmpty(g_stOperator);
scanf("%s",p);//获取输入的中缀表达式
changeStr(p);//将中缀表达式转换成后缀表达式
calculate(suffixStr);//通过后缀表达式进行计算
printf("%d", (int)g_stOperand->pNext->valueData);//打印出最后结果
//while(1);
return 0;
}
//清空栈的操作
void makeEmpty(stackList *stack)
{
if (stack == NULL)
printf("must creat stack first");
while(!isEmpty(stack))
pop(stack);
}
//判断栈是否为空
char isEmpty(stackList *stack)
{
return (stack->pNext == NULL);
}
//入栈操作
void push(stackList *stack, float data)
{
stackList *pTemp = (stackList *)malloc(sizeof(stackList));
if (stack == g_stOperand)//操作数入栈
{
if (pTemp == NULL)
return;
pTemp->valueData = data;
pTemp->pNext = stack->pNext;
stack->pNext = pTemp;
}
if (stack == g_stOperator)//操作符入栈
{
if (pTemp == NULL)
return;
pTemp->valueData = data;
pTemp->pNext = stack->pNext;
stack->pNext = pTemp;
}
}
//出栈操作
void pop(stackList *stack)
{
stackList *pTop = NULL;
if (isEmpty(stack))
return;
pTop = stack->pNext;
stack->pNext = stack->pNext->pNext;
free(pTop);
}
//计算
void calculate(char *p)
{
float a, b, t;
char temp[100];
int i = 0;
makeEmpty(g_stOperand);
makeEmpty(g_stOperator);
while(*p)
{
if((*p >= '0') && (*p <= '9'))
{
while((*p >= '0') && (*p <= '9'))
{
temp[i] = *p;
p++;
i++;
}
push(g_stOperand, atoi(temp));
memset(temp, 0, sizeof(temp));
i = 0;
}
if (*p == '+')
{
a = g_stOperand->pNext->valueData;
pop(g_stOperand);
b = g_stOperand->pNext->valueData;
pop(g_stOperand);
t = b + a;
push(g_stOperand, t);
}
if (*p == '-')
{
a = g_stOperand->pNext->valueData;
pop(g_stOperand);
b = g_stOperand->pNext->valueData;
pop(g_stOperand);
t = b - a;
push(g_stOperand, t);
}
if (*p == '*')
{
a = g_stOperand->pNext->valueData;
pop(g_stOperand);
b = g_stOperand->pNext->valueData;
pop(g_stOperand);
t = b * a;
push(g_stOperand, t);
}
if (*p == '/')
{
a = g_stOperand->pNext->valueData;
pop(g_stOperand);
b = g_stOperand->pNext->valueData;
pop(g_stOperand);
t = b / a;
push(g_stOperand, t);
}
p++;
}
}
void changeStr(char *p)
{
stackList *k = (stackList *)malloc(sizeof(stackList));
int i = 0;
k = g_stOperator;
while(*p)
{
if((*p >= '0') && (*p <= '9'))
{
while((*p >= '0') && (*p <= '9'))
{
suffixStr[i] = *p;
p++;
i++;
}
suffixStr[i++] = ',';
}
/*
'+' ------- 1
'-' ------- 2
'*' ------- 5
'/' ------- 6
*/
if (*p == '+')
{
if ( ( isEmpty(g_stOperator) ) )
push(g_stOperator, 1);
else if ( (g_stOperator->pNext->valueData - 1) > 2 )
{
while ( !isEmpty(g_stOperator) )
{
switch ((int)g_stOperator->pNext->valueData)
{
case 1: suffixStr[i++] = '+'; suffixStr[i++] = ','; break;
case 2: suffixStr[i++] = '-'; suffixStr[i++] = ','; break;
case 5: suffixStr[i++] = '*'; suffixStr[i++] = ','; break;
case 6: suffixStr[i++] = '/'; suffixStr[i++] = ','; break;
}
pop(g_stOperator);
}
push(g_stOperator, 1);
}
else
push(g_stOperator, 1);
p++;
}
if (*p == '-')
{
if ( ( isEmpty(g_stOperator) ) )
push(g_stOperator, 2);
else if ( (g_stOperator->pNext->valueData - 1) > 2 )
{
while ( !isEmpty(g_stOperator) )
{
switch ((int)g_stOperator->pNext->valueData)
{
case 1: suffixStr[i++] = '+'; suffixStr[i++] = ','; break;
case 2: suffixStr[i++] = '-'; suffixStr[i++] = ','; break;
case 5: suffixStr[i++] = '*'; suffixStr[i++] = ','; break;
case 6: suffixStr[i++] = '/'; suffixStr[i++] = ','; break;
}
pop(g_stOperator);
}
push(g_stOperator, 2);
}
else
push(g_stOperator, 2);
p++;
}
if (*p == '*')
{
push(g_stOperator, 5);
p++;
}
if (*p == '/')
{
push(g_stOperator, 6);
p++;
}
}
while ( !isEmpty(g_stOperator) )
{
switch ((int)g_stOperator->pNext->valueData)
{
case 1: suffixStr[i++] = '+'; suffixStr[i++] = ','; break;
case 2: suffixStr[i++] = '-'; suffixStr[i++] = ','; break;
case 5: suffixStr[i++] = '*'; suffixStr[i++] = ','; break;
case 6: suffixStr[i++] = '/'; suffixStr[i++] = ','; break;
}
pop(g_stOperator);
}
}