NOIP 2000 计算器的改良 解题报告

　　简单的模拟吧，大家都尝试尝试~~不太难，代码：

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
char str[101];
char c;

char *getval(char *str, int *i)
{
	int t = 0, m = 0;
	if(str[0] == '-'){
		m = 1;
		str++;
	}else if(str[0] == '+'){
		str++;
	}
	while(isdigit(*str)){
		t *= 10;
		t += *str - '0';
		str++;
	}
	if(m){
		t *= -1;
	}
	*i = t;
	return str;
}

void srch(char *str, int *n, int *x, int l)
{
	int i;
	do{
		str = getval(str, &i);
		if(isalpha(str[0])){
			c = str[0];
			str++;
			*x += l * i;
		}else{
			*n += l * i;
		}
	}while(*str != '\0');
}

int main(int argc, char **argv)
{
	int n = 0, x = 0;
	char *p;
	scanf("%s", str);
	p = strchr(str, '=');
	*p = '\0';
	srch(str, &n, &x, 1);
	srch(p + 1, &n, &x, -1);
	printf("%c=%.3lf\n", c, (double)-n/x);
	return 0;
}