C++24点游戏

原创，代码：

#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<ctime>
#include<windows.h>
#include<string>
using namespace std;
int a[4],o[3];
bool f;
string s,ans;
void clr() {
	system("cls");
}
bool v(int c) {
	return c=='+'||c=='-'||c=='*'||c=='/';
}
double cal(double x,double y,int op) {
	switch(op) {
		case'+':
			return x+y;
		case'-':
			return x-y;
		case'*':
			return x*y;
		case'/':
			return y?x/y:-1e9;
	}
	return 0;
}
double cal(double x,double y,int op,string &s1,string &s2,string &res) {
	res="("+s1+char(op)+s2+")";
	switch(op) {
		case'+':
			return x+y;
		case'-':
			return x-y;
		case'*':
			return x*y;
		case'/':
			return y?x/y:-1e9;
	}
	return 0;
}
void findans() {
	int p[4]= {0,1,2,3},op1,op2,op3;
	string s1,s2,s3,s4,t1,t2,t3,r;
	double v1,v2,v3;
	do {
		for(op1='+'; op1<='/'&&!ans.size(); op1+=13) {
			for(op2='+'; op2<='/'&&!ans.size(); op2+=13) {
				for(op3='+'; op3<='/'&&!ans.size(); op3+=13) {
					s1=to_string(a[p[0]]);
					s2=to_string(a[p[1]]);
					s3=to_string(a[p[2]]);
					s4=to_string(a[p[3]]);
					v1=cal(a[p[0]],a[p[1]],op1,t1,t2,t1);
					v2=cal(v1,a[p[2]],op2,t1,s3,t2);
					v3=cal(v2,a[p[3]],op3,t2,s4,t3);
					if(v3>23.999&&v3<24.001)ans=t1+"="+to_string((int)v1)+","+t2+"="+to_string((int)v2)+","+t3+"=24";
					if(ans.size())return;
					v1=cal(a[p[0]],a[p[1]],op1,t1,t2,t1);
					v2=cal(a[p[2]],a[p[3]],op3,s3,s4,t2);
					v3=cal(v1,v2,op2,t1,t2,t3);
					if(v3>23.999&&v3<24.001)ans=t1+"="+to_string((int)v1)+","+t2+"="+to_string((int)v2)+","+t3+"=24";
					if(ans.size())return;
				}
			}
		}
	} while(next_permutation(p,p+4)&&!ans.size());
}
void gen() {
	do {
		ans="";
		for(int i=0; i<4; i++)a[i]=rand()%9+1;
		findans();
	} while(ans.empty());
}
void chk(int n,int m,int p,int q,int o1,int o2,int o3) {
	string s1=to_string(a[n]),s2=to_string(a[m]),s3=to_string(a[p]),s4=to_string(a[q]);
	string t1,t2,t3,r;
	double v1,v2,v3;
	v1=cal(a[n],a[m],o1,t1,t2,t1);
	v2=cal(v1,a[p],o2,t1,s3,t2);
	v3=cal(v2,a[q],o3,t2,s4,t3);
	if(v3>23.999&&v3<24.001) {
		f=1;
		s=t1+"="+to_string((int)v1)+","+t2+"="+to_string((int)v2)+","+t3+"=24";
		return;
	}
	v1=cal(a[n],a[m],o1,t1,t2,t1);
	v2=cal(a[p],a[q],o3,s3,s4,t2);
	v3=cal(v1,v2,o2,t1,t2,t3);
	if(v3>23.999&&v3<24.001) {
		f=1;
		s=t1+"="+to_string((int)v1)+","+t2+"="+to_string((int)v2)+","+t3+"=24";
		return;
	}
}
void d() {
	int p[4]= {0,1,2,3};
	do {
		chk(p[0],p[1],p[2],p[3],o[0],o[1],o[2]);
		if(f)return;
		chk(p[0],p[2],p[1],p[3],o[1],o[0],o[2]);
		if(f)return;
		chk(p[0],p[1],p[3],p[2],o[0],o[2],o[1]);
		if(f)return;
	} while(next_permutation(p,p+4));
}
int main() {
	srand(time(0));
	char r,c;
	do {
		clr();
		f=0;
		s="";
		gen();
		cout<<"数字:"<<a[0]<<","<<a[1]<<","<<a[2]<<","<<a[3]<<endl;
		cout<<"输入3个运算符(+-*/),或输入?查看答案:";
		cin>>c;
		if(c=='?') {
			cout<<"答案:"<<ans<<endl;
			goto e;
		} else {
			char c2,c3;
			cin>>c2>>c3;
			if(!v(c)||!v(c2)||!v(c3)) {
				cout<<"运算符不合法!"<<endl;
				goto e;
			}
			o[0]=c;
			o[1]=c2;
			o[2]=c3;
			d();
			if(f) {
				cout<<"成功组成24点!"<<endl;
				cout<<"运算流程:"<<s<<endl;
			} else {
				cout<<"不正确!正确答案:"<<ans<<endl;
			}
		}
e:
		cout<<"继续游戏?(y/n):";
		cin>>r;
	} while(r=='y'||r=='Y');
	clr();
	cout<<"欢迎下次光临!"<<endl;
	return 0;
}