王道计算机考研 数据结构C语言复现-第八章-中缀表达式求值

 这篇文章收录了王道考研课程中涉及的数据结构的所有代码。此外，本博客可能会添加一些额外的代码（不仅限于王道考研），因为408考试中会频繁考察一些冷门的知识点，所以这篇博客会涵盖所有相关的代码。这也是我数据结构的第一轮复习，希望能与大家共同进步。由于博客篇幅的限制，可能无法一次性包含所有内容，欢迎指出代码错误部分！！！

你想要的都在下面！！！

// @FileName  :08ZhongZhuiBiaoDaShi.c
// @Time      :2023/8/15 16:46
// @Author    :YKW
//Scratch.c
#include 
#include 
#include 
#include 
#include 
#define maximum 100000

typedef struct//数字栈
{
    float data[maximum];
    int top;
}number;

typedef struct//字符栈
{
    char data[maximum];
    int top;
}sign;

void InitNumber(number *stack);//初始化数字栈
void GetTopNumber(number stack, float *e);//获取栈顶元素
void PushNumber(number *stack, float e);//进栈
void PopNumber(number *stack, float *e);//出栈

void InitSign(sign *stack);
void GetTopSign(sign stack, char *e);
void PushSign(sign *stack, char e);
void PopSign(sign *stack, char *e);

void Calculate(number *stack, char e);

number Num;
sign sig;
char expression[maximum];

int main()
{
    gets(expression);
    int length;
    length=strlen(expression);
    int i;
    float en,n;
    char es;
    InitNumber(&Num);
    InitSign(&sig);
    for (i=0;i='0'&&expression[i]<='9')
        {
            n=expression[i]-'0';//字符型转换为整型
            while (expression[i+1]!='\0')
            {
                if (expression[i+1]>='0'&&expression[i+1]<='9')
                {
                    n=n*10+expression[i+1]-'0';
                    ++i;
                }
                else break;
            }
            PushNumber(&Num,n);
        }
        else if (expression[i]=='+'||expression[i]=='-'||expression[i]=='*'||expression[i]=='/'||expression[i]=='^'||expression[i]=='('||expression[i]==')')
        {
            switch (expression[i])
            {
                case '+':
                    if(sig.data[sig.top-1]!='+'&&sig.data[sig.top-1]!='-'&&sig.data[sig.top-1]!='*'&&sig.data[sig.top-1]!='/'&&sig.data[sig.top-1]!='^')
                        //与栈顶元素的优先级相比较， 高于时入栈，此处判断是否入栈。
                        PushSign(&sig,'+');
                    else
                    {
                        while (sig.top>0&&sig.data[sig.top-1]!='(')//如果栈不为空切不为左括号，则出栈
                        {
                            PopSign(&sig,&es);
                            Calculate(&Num,es);
                        }
                        PushSign(&sig,'+');
                    }
                    break;
                case '-':
                    if(sig.data[sig.top-1]!='+'&&sig.data[sig.top-1]!='-'&&sig.data[sig.top-1]!='*'&&sig.data[sig.top-1]!='/'&&sig.data[sig.top-1]!='^')
                        PushSign(&sig,'-');
                    else
                    {
                        while (sig.top>0&&sig.data[sig.top-1]!='(')
                        {
                            PopSign(&sig,&es);
                            Calculate(&Num,es);
                        }
                        PushSign(&sig,'-');
                    }
                    break;
                case '*':
                    if(sig.data[sig.top-1]!='*'&&sig.data[sig.top-1]!='/'&&sig.data[sig.top-1]!='^')
                        PushSign(&sig,'*');
                    else
                    {
                        while (sig.top>0&&sig.data[sig.top-1]!='(')
                        {
                            PopSign(&sig,&es);
                            Calculate(&Num,es);
                        }
                        PushSign(&sig,'*');
                    }
                    break;
                case '/':
                    if(sig.data[sig.top-1]!='*'&&sig.data[sig.top-1]!='/'&&sig.data[sig.top-1]!='^')
                        PushSign(&sig,'/');
                    else
                    {
                        while (sig.top>0&&sig.data[sig.top-1]!='(')
                        {
                            PopSign(&sig,&es);
                            Calculate(&Num,es);
                        }
                        PushSign(&sig,'/');
                    }
                    break;
                case '^':
                    if(sig.data[sig.top-1]!='^')
                        PushSign(&sig,'^');
                    else
                    {
                        while (sig.top>0&&sig.data[sig.top-1]!='(')
                        {
                            PopSign(&sig,&es);
                            Calculate(&Num,es);
                        }
                        PushSign(&sig,'^');
                    }
                case '(':
                    PushSign(&sig,'(');
                    break;
                case ')':
                    while (sig.data[sig.top-1]!='(')
                    {
                        PopSign(&sig,&es);
                        Calculate(&Num,es);
                    }
                    PopSign(&sig,&es);
            }
        }
    }
    while (sig.top>0)
    {
        PopSign(&sig,&es);
        Calculate(&Num,es);
    }
    GetTopNumber(Num,&en);
    printf("%.0f\n",en);
    return 0;
}

void InitNumber(number *stack)
{
    stack->top=0;
}

void GetTopNumber(number stack, float *e)
{
    if(stack.top==0) return;
    else *e=stack.data[stack.top-1];
}

void PushNumber(number *stack, float e)
{
    if(stack->top>=maximum) return;
    else stack->data[stack->top++]=e;
}

void PopNumber(number *stack, float *e)
{
    if(stack->top==0) return;
    else *e=stack->data[--stack->top];
}

void InitSign(sign *stack)
{
    stack->top=0;
}

void GetTopSign(sign stack, char *e)
{
    if(stack.top==0) return;
    else *e=stack.data[stack.top-1];
}

void PushSign(sign *stack, char e)
{
    if(stack->top>=maximum) return;//栈满
    else
    {
        stack->data[stack->top]=e;
        stack->top++;
    }
}

void PopSign(sign *stack, char *e)
{
    if(stack->top==0) return;
    else *e=stack->data[--stack->top];
}

void Calculate(number *stack, char e)// 计算结果
{
    float num1,num2,result;
    PopNumber(stack, &num2);
    PopNumber(stack, &num1);
    switch (e)
    {
        case '+':
            result=num1+num2;
            PushNumber(stack,result);
            break;
        case '-':
            result=num1-num2;
            PushNumber(stack,result);
            break;
        case '*':
            result=num1*num2;
            PushNumber(stack,result);
            break;
        case '/':
            if (num2==0) printf("表达式错误！");
            else
            {
                result=num1/num2;
                PushNumber(stack,result);
                break;
            }
        case '^':
            result=pow(num1,num2);
            PushNumber(stack,result);
            break;
    }
}