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

int priority(char op) {
    switch(op) {
        case '+' : case '-' : return 1;
        case '*' : case '/' : case '%' : return 2;
        case '^' : return 3;
        default : return 0;
    }
}

void printf_postfix(char str[105][10], int len) {
    int i = 0;
    for (i = 0; i < len; i++) {
        if (str[i][0] != '0') printf("%s ", str[i]);
    }
    printf("\n");
}

double cal(char op, double p1, double p2) {
    switch(op) {
        case '+' : return p1 + p2;
        case '-' : return p1 - p2;
        case '*' : return p1 * p2;
        case '/' : return p1 / p2;
        case '%' : return (int)p1 % (int)p2;
        case '^' : return pow(p1, p2);
    }
}

void oper(char str[105][10], int len) {
    double now[105] = {0.0};

    int L = 0, top = 0;
    while (L < len) {
        switch(str[L][0]) {
            case '+' : case '-' : case '*' : case '/' : case '%' : case '^' :
                now[top-1] = cal(str[L][0], now[top-1], now[top]);
                top--;
                break;
            default :
                now[++top] = atof(str[L]);
        }
        L++;
    }
    printf("\n運算結果=%5f\n\n", now[top]);
}

void infix_to_postfix(char* str) {
    char infix[105][10] = {' '}, stack[105], now[10];

    int L = 0, R = 0, top = 0, i, j, flag = 0;
    while (str[L] != '\0') {
        switch(str[L]) {
            case '(' :
                stack[++top] = str[L];
                if (str[L+1] == '-') { flag = 1; L++; }
                break;
            case ')' :
                while (stack[top] != '(') {
                    infix[R++][0] = stack[top--];
                }
                top--;
                break;
            case '+' : case '-' : case '*' : case '/' : case '%' : case '^' :
                while (priority(stack[top]) >= priority(str[L])) {
                    infix[R++][0] = stack[top--];
                }
                stack[++top] = str[L];
                if (str[L+1] == '-') { flag = 1; L++; }
                break;
            default :
                i = 0;
                while (str[L] == '.' || (str[L] >= '0' && str[L] <= '9')) {
                    now[i++] = str[L++];
                }
                if (flag) {
                    infix[R][0] = '0'; infix[R+2][0] = '-'; flag = 0;
                    for (j = 0; j < i; j++) infix[R+1][j] = now[j];
                    R += 2;
                } else {
                    for (j = 0; j < i; j++) infix[R][j] = now[j];
                }
                L--; R++;
        }
        L++;
    }

    while (top) {
        infix[R++][0] = stack[top--];
    }

    printf_postfix(infix, R);
    oper(infix, R);
}

int main() {
    printf("%5f", 1+sin((-50.2+sin(3.8*20)*cos(-30-100%40))*pow(2, -2.5))*cos(123.456));
    char str[105] = {'\0'};
    while (printf("輸入中序式(支援+ - * / ^ () sin() cos()運算) => ")) {
        scanf("%s", str);

        printf("\n對應的後序式：");
        infix_to_postfix(str);
    }
    return 0;
}

/*
10+20*(50-30)/2^4-6*8
10.5+20.8*(50.1-30.6)/2.5^4-6.6*8.2
10-30*(-40-20)%2^4+7.5*-6
1+sin((-50.2+sin(3.8*20)*cos(-30-100%40))*2^-2.5)*cos(123.456)
*/