lab3_1

#include <stdio.h>
#include "mystack.h"

void polska(char ar1[], char ar2[]);

main()
{
    char infix[SIZE], postfix[SIZE];
    FILE *ifp, *ofp;
    int i = 0;

    ifp = fopen("input.txt", "r");

    while ( !feof(ifp) ) {
        fscanf(ifp, "%c", &infix[++i]);
    }

    fclose(ifp);

    infix[0] = i;

    polska(infix, postfix);

    ofp = fopen("output.txt", "w");

    for (i = 1; i <= postfix[0]; i++) {
        fprintf(ofp, "%c ", postfix[i]);
    }

    fprintf(ofp, "\n");

    fclose(ofp);

    return 0;
}

int prior(char sign)
{
    switch(sign) {
        case '*':case '/': return 2;
                           break;
        case '+':case '-': return 1;
                           break;
    }

    return 0;
}

void polska(char inf[], char post[])
{
    Stack S;
    int i, j = 0;
    char curr_char, smbl;

    init(&S);

    for (i = 1; i <= inf[0]; i++) {
        switch ( curr_char = inf[i] ) {
            case '0':case '1':case '2':case '3':case '4':case '5':
            case '6':case '7':case '8':case '9':
                post[++j] = curr_char;
                break;

            case '+':case '-':case '*':case '/':
                if ((empty(&S) == 1) || (prior(curr_char) > prior(showtop(&S))))
                    push(&S, curr_char);
                else {
                        while (prior(curr_char) <= prior(showtop(&S)))
                            post[++j] = pop(&S);
                        push(&S, curr_char);
                }
                break;

            case '(': push(&S, curr_char);
                      break;

            case ')': while ( (smbl = pop(&S)) != '(' ) {
                          post[++j] = smbl;
                      }
                      break;
            default:  break;
        }
    }

    while ( empty(&S) != 1)
        post[++j] = pop(&S);

    post[0] = j;

    return;
}