寄录

好像是读到了回车

#include <iostream>
using namespace std;

long long ans;
char wz;
int xishu;
void read(){
	char c = getchar();
	int p = -1,p2 = 1,sum = 0;
	while (c!='\n'){
		if (c >= '0' && c <= '9'){
			sum = (sum<<1) + (sum<<3) + (c^48);
		}else if (c == '='){
			ans += sum*p*p2;
			sum = 0;
			p *= -1;
		}else if (c == '-'){
			ans += sum*p*p2;
			sum = 0;
			p2 = -1;
		}else if (c == '+'){
			ans += sum*p*p2;
			sum = 0;
			p2 = 1;
		}
		else {
			if (sum*p*p2 == 0) xishu += p*p2;
			else xishu += sum*p*p2;;
			sum = 0;
			wz = c;
		}
		//cout << c << "\n";
		c = getchar();
		//cout << sum << " " << ans << "\n"; 
	}
	ans += sum*p*p2;
}
int main(){
	read();
	printf("%c=%.3lf",wz,ans*1.0/(-xishu));
}