main.c

#include <reg52.h>
#include <intrins.h>

// --- 硬件定义 ---
#define LCD_DATA P0
sbit LCD_RS = P2^6;
sbit LCD_RW = P2^5;
sbit LCD_EN = P2^7;

#define KEY_MATRIX P1

// 独立按键 P3
sbit Key_BracL = P3^0; 
sbit Key_BracR = P3^1; 
sbit Key_Dot   = P3^2; 
sbit Key_Del   = P3^3; 
sbit Key_Clr   = P3^4; 
sbit Key_Equ   = P3^5; 

// --- 内存定义 ---
#define MAX_BUFFER 64
char xdata inputBuf[MAX_BUFFER + 1]; 
unsigned char bufIdx = 0;

// UI状态控制
bit isWelcome = 1;  
bit calcDone = 0;   
bit isError = 0;    

// 栈定义
#define STACK_DEPTH 20
float xdata numStack[STACK_DEPTH];     
char xdata opStack[STACK_DEPTH];       
signed char numTop = -1;
signed char opTop = -1;

// --- 编译原理状态定义 ---
typedef enum {
    S_START = 0, S_NUM, S_OP, S_DOT, S_LBRAC, S_RBRAC      
} ParserState;

// --- 基础延时 ---
void DelayMs(unsigned int ms) {
    unsigned int i, j;
    for(i=0; i<ms; i++) for(j=0; j<110; j++);
}

// --- LCD1602 驱动 ---
void LCD_WriteCmd(unsigned char cmd) {
    LCD_RS = 0; LCD_RW = 0; LCD_DATA = cmd;
    DelayMs(1); LCD_EN = 1; DelayMs(1); LCD_EN = 0;
}
void LCD_WriteData(unsigned char dat) {
    LCD_RS = 1; LCD_RW = 0; LCD_DATA = dat;
    DelayMs(1); LCD_EN = 1; DelayMs(1); LCD_EN = 0;
}
void LCD_Init() {
    LCD_WriteCmd(0x38); LCD_WriteCmd(0x0c);
    LCD_WriteCmd(0x06); LCD_WriteCmd(0x01);
}
void LCD_ShowStr(unsigned char x, unsigned char y, char *str) {
    if(y==0) LCD_WriteCmd(0x80|x); else LCD_WriteCmd(0x80|0x40|x);
    while(*str) LCD_WriteData(*str++);
}

// --- UI显示逻辑 ---
void UpdateLine1_Input() {
    unsigned char i;
    LCD_WriteCmd(0x80); 
    if(bufIdx <= 16) {
        for(i=0; i<bufIdx; i++) LCD_WriteData(inputBuf[i]);
        for(i=bufIdx; i<16; i++) LCD_WriteData(' '); 
    } else {
        for(i=bufIdx-16; i<bufIdx; i++) LCD_WriteData(inputBuf[i]);
    }
}

void ShowLine2_Result(char *str) {
    unsigned char i = 0;
    LCD_WriteCmd(0x80 | 0x40); 
    while(str[i] && i < 16) {
        LCD_WriteData(str[i]);
        i++;
    }
    while(i < 16) {
        LCD_WriteData(' ');
        i++;
    }
}

// --- 辅助工具 ---
bit IsDigit(char c) { return (c >= '0' && c <= '9'); }
bit IsOperator(char c) { return (c == '+' || c == '-' || c == '*' || c == '/'); }

// --- 文法检查 (DFA) ---
bit SyntaxCheck(char* str) {
    ParserState state = S_START;
    int bracketBalance = 0; 
    char c;
    int i = 0;

    while(str[i] != '\0') {
        c = str[i];
        switch(state) {
            case S_START:
                if(IsDigit(c)) state = S_NUM;
                else if(c == '(') { state = S_LBRAC; bracketBalance++; }
                else if(c == '-') state = S_NUM; 
                else return 0; 
                break;
            case S_NUM:
                if(IsDigit(c)) state = S_NUM;
                else if(c == '.') state = S_DOT;
                else if(IsOperator(c)) state = S_OP;
                else if(c == ')') { state = S_RBRAC; bracketBalance--; if(bracketBalance < 0) return 0; }
                else return 0;
                break;
            case S_DOT:
                if(IsDigit(c)) state = S_NUM; else return 0; 
                break;
            case S_OP:
                if(IsDigit(c)) state = S_NUM;
                else if(c == '(') { state = S_LBRAC; bracketBalance++; }
                else return 0; 
                break;
            case S_LBRAC:
                if(IsDigit(c)) state = S_NUM;
                else if(c == '(') { state = S_LBRAC; bracketBalance++; }
                else if(c == '-') state = S_NUM; 
                else return 0; 
                break;
            case S_RBRAC:
                if(IsOperator(c)) state = S_OP;
                else if(c == ')') { state = S_RBRAC; bracketBalance--; if(bracketBalance < 0) return 0; }
                else return 0; 
                break;
        }
        i++;
    }
    if(bracketBalance != 0) return 0;
    if(state == S_NUM || state == S_RBRAC) return 1;
    return 0;
}

// --- 计算核心 ---
float MyStrToFloat(char *str) {
    float res = 0.0;
    float factor = 1.0;
    bit hasDot = 0;
    while(*str) {
        if(*str == '.') hasDot = 1;
        else if(IsDigit(*str)) {
            if(!hasDot) res = res * 10 + (*str - '0');
            else { factor *= 10.0; res += (*str - '0') / factor; }
        }
        else break; 
        str++;
    }
    return res;
}

void pushNum(float val) { if(numTop < STACK_DEPTH-1) numStack[++numTop] = val; }
float popNum() { return (numTop >= 0) ? numStack[numTop--] : 0; }
void pushOp(char op) { if(opTop < STACK_DEPTH-1) opStack[++opTop] = op; }
char popOp() { return (opTop >= 0) ? opStack[opTop--] : 0; }
char peekOp() { return (opTop == -1) ? 0 : opStack[opTop]; }

unsigned char getPriority(char op) {
    if(op == '+' || op == '-') return 1;
    if(op == '*' || op == '/') return 2;
    return 0;
}

void calcTop() {
    float b = popNum();
    float a = popNum();
    char op = popOp();
    float res = 0;
    
    if(op == '/' && (b > -0.000001 && b < 0.000001)) {
        isError = 1; 
    } else {
        if(op == '+') res = a + b;
        else if(op == '-') res = a - b;
        else if(op == '*') res = a * b;
        else if(op == '/') res = a / b;
        pushNum(res);
    }
}

float CalculateResult(char* str) {
    unsigned char i = 0;
    float val;
    numTop = -1; opTop = -1;
    isError = 0;
    
    while(str[i] != '\0') {
        if(isError) break;
        if(IsDigit(str[i]) || str[i] == '.') {
            val = MyStrToFloat(&str[i]);
            pushNum(val);
            while(IsDigit(str[i]) || str[i] == '.') i++;
        }
        else if(str[i] == '(') { pushOp('('); i++; }
        else if(str[i] == ')') {
            while(opTop != -1 && peekOp() != '(') { calcTop(); if(isError) break; }
            if(!isError) popOp();
            i++;
        }
        else if(IsOperator(str[i])) {
            while(opTop != -1 && peekOp() != '(' && getPriority(peekOp()) >= getPriority(str[i])) {
                calcTop(); if(isError) break;
            }
            pushOp(str[i]); i++;
        }
        else i++;
    }
    while(opTop != -1 && !isError) calcTop();
    return numStack[0];
}

// --- 结果转字符串 (四舍五入回归版) ---
void FloatToResultStr(float val, char* outStr) {
    long intPart;
    float frac;
    int i = 0, k;
    char temp[16];
    int tIdx = 0;
    
    outStr[i++] = '=';
    
    if(val < 0) {
        outStr[i++] = '-';
        val = -val;
    }
    
    // 【修正】重新启用四舍五入校正
    // 这是为了解决 15.98 这种二进制无限小数的显示问题
    val += 0.000005; 

    // 1. 提取整数
    intPart = (long)val;
    if(intPart == 0) temp[tIdx++] = '0';
    else {
        long t = intPart;
        while(t > 0) { temp[tIdx++] = (t % 10) + '0'; t /= 10; }
    }
    for(k=tIdx-1; k>=0; k--) outStr[i++] = temp[k];
    
    // 2. 提取小数
    frac = val - intPart;
    if(frac > 0.00001) { 
        outStr[i++] = '.';
        for(k=0; k<5; k++) { 
            frac *= 10;
            outStr[i++] = (char)frac + '0';
            frac -= (char)frac;
        }
        
        // 3. 去除尾部多余的0
        while(outStr[i-1] == '0') i--;
        if(outStr[i-1] == '.') i--; 
    }
    outStr[i] = '\0'; 
}

// --- 键盘处理 ---
void HandleInput(char key) {
    float res;
    char xdata resStr[17]; 

    // 欢迎页处理
    if(isWelcome) {
        LCD_WriteCmd(0x01); 
        isWelcome = 0;
        bufIdx = 0; inputBuf[0] = '\0';
        UpdateLine1_Input(); 
        if(key == 'C') return; 
    }

    if(key == 'C') { 
        bufIdx = 0; inputBuf[0] = '\0';
        calcDone = 0;
        UpdateLine1_Input();
        ShowLine2_Result(""); 
        return;
    }
    
    if(key == 'D') { 
        if(bufIdx > 0 && !calcDone) { 
            bufIdx--; inputBuf[bufIdx] = '\0';
            UpdateLine1_Input();
            ShowLine2_Result(""); 
        }
        return;
    }
    
    if(key == '=') {
        if(!calcDone && bufIdx > 0) { 
            if(!SyntaxCheck(inputBuf)) {
                ShowLine2_Result("Syntax Error!");
                calcDone = 1; 
                return;
            }
            
            res = CalculateResult(inputBuf);
            
            if(isError) {
                ShowLine2_Result("Math Error!");
                calcDone = 1;
                return;
            }
            
            FloatToResultStr(res, resStr);
            ShowLine2_Result(resStr);
            
            calcDone = 1; 
        }
        return;
    }
    
    if(calcDone) {
        bufIdx = 0; inputBuf[0] = '\0';
        calcDone = 0;
        ShowLine2_Result(""); 
        UpdateLine1_Input();
    }
    
    if(bufIdx < MAX_BUFFER) {
        inputBuf[bufIdx++] = key;
        inputBuf[bufIdx] = '\0';
        UpdateLine1_Input(); 
    }
}

// --- 扫描函数 ---
char MatrixKeyScan() {
    unsigned char h, l;
    KEY_MATRIX = 0x0f; h = KEY_MATRIX & 0x0f;
    if (h != 0x0f) {
        DelayMs(10); if((KEY_MATRIX & 0x0f) != 0x0f) {
            h = KEY_MATRIX & 0x0f; KEY_MATRIX = h | 0xf0; l = KEY_MATRIX & 0xf0;
            while((KEY_MATRIX & 0xf0) != 0xf0); 
            switch(l+h) {
                case 0xee: return '1'; case 0xde: return '2'; case 0xbe: return '3'; case 0x7e: return '+';
                case 0xed: return '4'; case 0xdd: return '5'; case 0xbd: return '6'; case 0x7d: return '-';
                case 0xeb: return '7'; case 0xdb: return '8'; case 0xbb: return '9'; case 0x7b: return '*';
                case 0xe7: return '0'; case 0xd7: return '0'; case 0xb7: return '0'; case 0x77: return '/';
            }
        }
    }
    return 0;
}
char IndepKeyScan() {
    if(!Key_BracL) { DelayMs(20); if(!Key_BracL) { while(!Key_BracL); return '('; } }
    if(!Key_BracR) { DelayMs(20); if(!Key_BracR) { while(!Key_BracR); return ')'; } }
    if(!Key_Dot)   { DelayMs(20); if(!Key_Dot)   { while(!Key_Dot);   return '.'; } }
    if(!Key_Del)   { DelayMs(20); if(!Key_Del)   { while(!Key_Del);   return 'D'; } } 
    if(!Key_Clr)   { DelayMs(20); if(!Key_Clr)   { while(!Key_Clr);   return 'C'; } } 
    if(!Key_Equ)   { DelayMs(20); if(!Key_Equ)   { while(!Key_Equ);   return '='; } }
    return 0;
}

void main() {
    char key;
    LCD_Init();
    LCD_ShowStr(0, 0, "Calculator By zzy"); 
    LCD_ShowStr(0, 1, "                "); 

    while(1) {
        key = MatrixKeyScan();
        if(key == 0) key = IndepKeyScan();
        
        if(key != 0) {
            HandleInput(key);
        }
    }
}