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#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "stack.h"
char *readword(FILE *f) {
if (getc(f) == EOF) return NULL;
fseek(f, -1, SEEK_CUR);
char *word = malloc(10);
char c;
int i = 0;
while ((c = getc(f)) != ' ') {
if (c == EOF || c == '\n') break;
word[i] = c;
i++;
}
word[i] = 0;
return word;
}
int main() {
FILE *f = fopen("test.rpn", "r");
stack *s = initstack(0 ,100);
char *word;
int a, b;
while ((word = readword(f)) != NULL) {
if (!isdigit(word[0])) {
b = pop(s);
a = pop(s);
switch (word[0]) {
case '+': push(s, a+b); break;
case '-': push(s, a-b); break;
case '*': push(s, a*b); break;
case '/': push(s, a/b); break;
case '^': push(s, pow(a, b)); break;
case '~':
push(s, a);
push(s, -b);
break;
default:
printf("unknown symbol %c\n",word[0]);
exit(1);
break;
}
}
else push(s, atoi(word));
free(word);
}
printf("%d\n", pop(s));
deinitstack(s);
}
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