学习贺利坚老师,计算机混合运算, 做出处理混合运算

数据结构例程——表达式求值（用栈结构）_用栈表达式求值-CSDN博客文章浏览阅读1.5w次，点赞14次，收藏61次。本文针对数据结构基础系列网络课程(3)：栈和队列中第5课时栈的应用1-表达式求值。例：用户输入一个包含“+”、“-”、“*”、“/”、正整数和圆括号的合法数学表达式，计算该表达式的运算结果。 解答：#include #include #define MaxOp 100#define MaxSize 100struct //设定运算符优先级{_用栈表达式求值https://blog.csdn.net/sxhelijian/article/details/48464683本人详细解析博客:

        用后缀式解决混合运算

计算器的混合运算_wnt-2135计算器复合运算-CSDN博客文章浏览阅读1.4k次，点赞8次，收藏12次。我们日常生活中 , 处处离不开计算 ,简单的买菜 , 去超市购物等 , 都需要计算消费的金额 , 我们一次性买了很多种类的菜 , 同一种饮料买了好几瓶 . 如果用手算的话 , 我们当然不可能傻到一个算式一个算式的去计算结果 . 我们一般会列一个混合运算的式子 , 然后再计算.这时候 ,如果让一个一年级的小学生来算的话 ,他会感到一头雾水 , 到底先算哪一个 ,因为他现在只学了加减法 ,只会逐步计算.我们学过算术优先级的同学 , 当然知道 , 我们要先算乘除, 再算加减 , 然后括号里的要优先运算 ._wnt-2135计算器复合运算https://blog.csdn.net/qq_57484399/article/details/127230655       由混合算式求后缀式

将混合运算表达式,转化为后缀表达式_将表达式 转为后缀表达式-CSDN博客文章浏览阅读757次，点赞4次，收藏5次。后缀式后缀式即逆波兰式，是逻辑学家卢卡西维奇（Lukasiewicz)发明的一种表示表达式的方法。这种表示方式把运算符写在运算对象的后面，例如，把a+b写成ab+，所以也称为后缀式。这种表示法的优点是根据运算对象和算符的出现次序进行计算，不需要使用括号，也便于用械实现求值。对于x:=(a+b)*(c+d)，其后缀式为xab+cd+*:=。原表达式：a*(b*(c+d/e)-f)# /* # 为表达式结束符号*/后缀式：abcde/+*f-*#为运算符定义优先级：# ( + - * / **_将表达式 转为后缀表达式https://blog.csdn.net/qq_57484399/article/details/127249659

更新日志:

v1.0: 实现基本运算功能

V1.0

#include <stdio.h>
#include <stdlib.h>

#define MaxOperate 7   //运算符数量
#define MaxSize 100


struct MyStructType
{
    char symbol;    //运算符
    char priority;  //优先级
};

//左运算符(进栈运算符)
MyStructType left_symbol[] =  {{'=',0},{'(',1},{'+',3},{'-',3},{'*',5},{'/',5},{')',6}};
//右运算符(待栈运算符)
MyStructType right_symbol[] = {{'=',0},{'(',6},{'+',2},{'-',2},{'*',4},{'/',4},{')',1}};

//求左运算符的优先级
int leftsymbol_priority(char seek_symbol)
{
    int counter;
    int result = 0;
    for(counter = 0; counter < MaxOperate; counter++)
    {
        if(left_symbol[counter].symbol ==  seek_symbol)
        {
            result = left_symbol[counter].priority;
        }

    }
    return result;
}


//求右运算符的优先级
int right_symbol_priority(char seek_symbol)
{
    int counter;
    int result = 0;
    for(counter = 0; counter < MaxOperate; counter++)
    {
        if(right_symbol[counter].symbol ==  seek_symbol)
        {
            result = right_symbol[counter].priority;
        }

    }
    return result;
}



bool judging_Type(char judge_char)
{
    if( judge_char == '(' ||
        judge_char == ')' ||
        judge_char == '+' ||
        judge_char == '-' ||
        judge_char == '*' ||
        judge_char == '/'  )
    {
        return true;    //是运算符
    }
    else
    {
        return false;   //不是运算符
    }

}

//operation1 和 operation2 运算符优先级的比较结果
int Comparative_priority(char operation1, char operation2)
{
    int result;
    if(leftsymbol_priority(operation1) == right_symbol_priority(operation2))
    {
        result = 0;
    }
    else
    if(leftsymbol_priority(operation1) < right_symbol_priority(operation2))
    {
        result = -1;
    }
    else
    {
        result = 1;
    }
    return result;

}

//将算数表达式 Mixed_operator 转换成后缀表达式 Suffix_expression
void Conversion_expression(char *Mixed_operator,char Suffix_expression[])
{
    int counter = 0;

    struct
    {
        char data[MaxSize];//存放运算符
        int top;            //栈指针
    }Operator_stack;

    Operator_stack.top = -1;
    Operator_stack.top++;
    Operator_stack.data[Operator_stack.top] = '=';

    //处理混合运算式
    while(*Mixed_operator != '\0')
    {
        //遍历到的字符为数字
        if(!judging_Type(*Mixed_operator))
        {
            while(*Mixed_operator >= '0' && *Mixed_operator <= '9') //把数字加入(从而过滤掉空格)
            {
                Suffix_expression[counter++] = *Mixed_operator;
                Mixed_operator++;
            }
            Suffix_expression[counter++] = '#'; //数字分隔符
        }
        else    //遍历到的字符为运算符
        {
            //比较栈顶运算符和此运算符
            switch(Comparative_priority(Operator_stack.data[Operator_stack.top],*Mixed_operator))
            {
                case -1://栈顶运算符优先级低:进栈
                    Operator_stack.top++;
                    Operator_stack.data[Operator_stack.top] = *Mixed_operator;
                    Mixed_operator++;
                    break;
                case 0: //只有括号满足这种情况,退栈,继续扫描
                    Operator_stack.top--;
                    Mixed_operator++;
                    break;
                case 1: //栈顶运算符高,则退栈并输出到 Suffix_expression
                    Suffix_expression[counter++] = Operator_stack.data[Operator_stack.top];
                    Operator_stack.top--;
                    break;
            }
        }
    }
    //把运算符栈内符号一次性出栈
    while(Operator_stack.data[Operator_stack.top] != '=')
    {
        Suffix_expression[counter] = Operator_stack.data[Operator_stack.top];
        counter++;
        Operator_stack.top--;
    }

    Suffix_expression[counter] = '\0';//为后缀式末尾增加结束符号
}

//计算后缀表达式的值
float Calculate_value(char Suffix_expression[])
{
    struct
    {
        float data[MaxSize];
        int top;
    }data_stack;//存储运算空间的栈
    //遍历字符串
    int counter = 0;
    //遍历字符串
    char visit_char = Suffix_expression[counter];
    //初始栈顶 -1
    data_stack.top = -1;
    //数字字符 转 数值中间变量
    float numerical_value;

    //根据后缀式,进行计算
    while(visit_char != '\0')
    {
        switch(visit_char)
        {
            case '+':
                data_stack.data[data_stack.top - 1] = data_stack.data[data_stack.top - 1] + data_stack.data[data_stack.top];
                data_stack.top--;
                counter++;
                break;
            case '-':
                data_stack.data[data_stack.top - 1] = data_stack.data[data_stack.top - 1] - data_stack.data[data_stack.top];
                data_stack.top--;
                counter++;
                break;
            case '*':
                data_stack.data[data_stack.top - 1] = data_stack.data[data_stack.top - 1] * data_stack.data[data_stack.top];
                data_stack.top--;
                counter++;
                break;
            case '/':
                if(data_stack.data[data_stack.top] != 0)
                {
                    data_stack.data[data_stack.top - 1] = data_stack.data[data_stack.top - 1] / data_stack.data[data_stack.top];
                    data_stack.top--;
                    counter++;
                }
                else    //除零错误
                {
                    printf("\n\t除零错误!\n");
                    exit(0);    //异常退出
                }
                break;
            default:
                numerical_value = 0;//将数字字符转换成数值存放在 numerical_value 中
                while(visit_char >= '0' && visit_char <= '9')
                {
                    numerical_value = 10 * numerical_value + visit_char - '0';
                    counter++;
                    visit_char = Suffix_expression[counter];
                }
                //处理数字入数据处理栈
                data_stack.top++;
                data_stack.data[data_stack.top] = numerical_value;
                counter++;//跳过后缀式数字后的'#'
                break;
        }
        //选中要处理的字符
        visit_char = Suffix_expression[counter];
    }

    //返回计算结果
    return data_stack.data[data_stack.top];
}


int main()
{
    //混合运算式
    char Mixed_operator[] = "(56-20)/(4+2)-33+9*32";//改为单片机输入
    //后缀表达式
    char Suffix_expression[MaxSize];
    //转换表达式(混合运算式 ==> 后缀表达式)
    Conversion_expression(Mixed_operator,Suffix_expression);
    printf("\n中缀表达式:%s\n",Mixed_operator);
    printf("\n后缀表达式:%s\n",Suffix_expression);
    printf("\n表达式的值:%g\n",Calculate_value(Suffix_expression));

    return 0;
}