用c语言编写四则混合运算的简易计算器

Question

支持小括号运算，简单的四则混合运算，用c语言

Answer 1

#include <cstdio>
#include <ctype.h>

struct eoe {
FILE* fp;
char token;
eoe() { fp = stdin; }
eoe(FILE* p) { fp = p; }
inline void getToken();
inline int exp();
inline int term();
inline int factor();
inline int result();
};

void eoe::getToken() {
while (1) {
token = fgetc(fp);
if (token == EOF || token == ';' || token == '=') {
token = 0; break;
} else if (!isspace(token)) break;
}
}

int eoe::exp() {
int t = term();
while (1) {
if (token == '+') getToken(), t += term();
else if (token == '-') getToken(), t -= term();
else break;
} return t;
}

int eoe::term() {
int t = factor();
while (1) {
if (token == '*') getToken(), t *= term();
else if (token == '/') getToken(), t /= term();
else break;
} return t;
}

int eoe::factor() {
int t;
if (token == '(') getToken(), t = exp(), getToken();
else if (isdigit(token)) ungetc(token, fp), fscanf(fp, "%d", &t), getToken();
return t;
}

int eoe::result() {
int t; getToken(); t = exp(); return t;
}

int main() {
eoe e;
printf("%d\n", e.result());
return 0;
}

Answer 2

我也想弄个这个题的答案，初学者，不会，呵呵