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#include "evalexpr.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define BUFFER_SIZE 10
char *get_input(void)
{
size_t r;
char buf[BUFFER_SIZE];
size_t size = 0;
char *expr = malloc(size * sizeof(char) + 1);
if (expr == NULL)
return NULL;
expr[0] = '\0';
do
{
r = fread(buf, sizeof(char), BUFFER_SIZE - 1, stdin);
if (r != 0)
{
buf[r] = '\0';
size += r;
char *tmp = realloc(expr, size * sizeof(char) + 1);
if (tmp == NULL)
{
free(expr);
return NULL;
}
expr = tmp;
strcat(expr, buf);
}
} while (r != 0);
if (size == 0)
{
free(expr);
return NULL;
}
if (expr[size - 1] == '\n')
expr[size - 1] = '\0';
return expr;
}
void cleanup(char *expr, char *rpn)
{
free(expr);
free(rpn);
}
int main(int argc, char **argv)
{
if ((argc == 2 && strcmp(argv[1], "-rpn") != 0) || (argc > 2))
return 4;
char *expr = get_input();
if (expr == NULL)
return 4;
if (argc == 1)
{
char *rpn;
int e = shunting_yard(expr, &rpn);
if (e != 0)
return e;
// call shunting yard
int retval;
e = evalrpn(rpn, &retval);
if (e != 0)
{
cleanup(expr, rpn);
return e;
}
// FREE RPN
printf("%d\n", retval);
cleanup(expr, rpn);
// return
return 0;
}
if (argc == 2 && strcmp(argv[1], "-rpn") == 0)
{
// call rpn eval
int retval;
int e = evalrpn(expr, &retval);
printf("%d\n", retval);
// return
free(expr);
if (e != 0)
return e;
return 0;
}
return 4;
}
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