我是一一举例的
#include<iostream>
using namespace std;void swap(float *a,float *b,float *c,float *d,int x)
{ float n,m,p,q; n=*a;m=*b;p=*c;q=*d; switch(x) { case 1:{*a=n;*b=m;*c=p;*d=q;};break; case 2:{*a=n;*b=m;*d=p;*c=q;};break; case 3:{*a=n;*c=m;*b=p;*d=q;};break; case 4:{*a=n;*c=m;*d=p;*b=q;};break; case 5:{*a=n;*d=m;*b=p;*c=q;};break; case 6:{*a=n;*d=m;*c=p;*b=q;};break; case 7:{*b=n;*a=m;*c=p;*d=q;};break; case 8:{*b=n;*a=m;*d=p;*c=q;};break; case 9:{*b=n;*c=m;*a=p;*d=q;};break; case 10:{*b=n;*c=m;*d=p;*a=q;};break; case 11:{*b=n;*d=m;*a=p;*c=q;};break; case 12:{*b=n;*d=m;*c=p;*a=q;};break; case 13:{*c=n;*a=m;*b=p;*d=q;};break; case 14:{*c=n;*a=m;*d=p;*b=q;};break; case 15:{*c=n;*d=m;*a=p;*b=q;};break; case 16:{*c=n;*d=m;*b=p;*a=q;};break; case 17:{*c=n;*b=m;*a=p;*d=q;};break; case 18:{*c=n;*b=m;*d=p;*a=q;};break; case 19:{*d=n;*a=m;*b=p;*c=q;};break; case 20:{*d=n;*a=m;*c=p;*b=q;};break; case 21:{*d=n;*b=m;*a=p;*c=q;};break; case 22:{*d=n;*b=m;*c=p;*a=q;};break; case 23:{*d=n;*c=m;*a=p;*b=q;};break; case 24:{*d=n;*c=m;*b=p;*a=q;};break; }}char fh(int i){ char r; if(i==1) r='+'; else if(i==2) r='-'; else if(i==3) r='*'; else r='/'; return r;}float suan(int i,float a,float b)
{ if(i==1) return a+b; else if(i==2) return a-b; else if(i==3) return a*b; else if(i==4) return a/b;}int qiude(float a,float b,float c,float d)
{int i1,i2,i3,n; float x,y,p,q,s=0,s1=0; x=a;y=b;p=c;q=d; for(n=1;n<=24;n++) { swap(&a,&b,&c,&d,n); for(i1=1;i1<=4;i1++) for(i2=1;i2<=4;i2++) for(i3=1;i3<=4;i3++) { s=suan(i1,a,b); s=suan(i2,s,c); s=suan(i3,s,d); if(s-24<0.001&&s-24>-0.001) { cout<<"(("<<a<<fh(i1)<<b<<")"<<fh(i2)<<c<<")"<<fh(i3)<<d<<"=24"<<endl; return 0; } else s=0; s=suan(i1,a,b); s=suan(i2,c,s); s=suan(i3,s,d); if(s-24<0.001&&s-24>-0.001) { cout<<"("<<c<<fh(i2)<<"("<<a<<fh(i1)<<b<<"))"<<fh(i3)<<d<<"=24"<<endl; return 0; } else s=0; s=suan(i1,a,b); s=suan(i2,s,c); s=suan(i3,d,s); if(s-24<0.001&&s-24>-0.001) { cout<<d<<fh(i3)<<"(("<<a<<fh(i1)<<b<<")"<<fh(i2)<<c<<")=24"<<endl; return 0; } else s=0; s=suan(i1,a,b); s=suan(i2,c,s); s=suan(i3,d,s); if(s-24<0.001&&s-24>-0.001) { cout<<d<<fh(i3)<<"("<<c<<fh(i2)<<"("<<a<<fh(i1)<<b<<"))=24"<<endl; return 0; } else s=0; } for(i1=1;i1<=4;i1++) for(i2=1;i2<=4;i2++) for(i3=1;i3<=4;i3++) { s=suan(i1,a,b); s1=suan(i3,c,d); s=suan(i2,s,s1); if(s-24<0.001&&s-24>-0.001) { cout<<"("<<a<<fh(i1)<<b<<")"<<fh(i2)<<"("<<c<<fh(i3)<<d<<")"<<"=24"<<endl; return 0; } else s=0;}
a=x;b=y;c=p;d=q; } cout<<"无法算得24点。"<<endl; return 0;}int main(){ float a=0,b=0,c=0,d=0; cout<<"要算24点吗？四个数之间以空格分开，要结束程序输-1."<<endl; while(a!=-1) { cin>>a; if(a==-1) break; cin>>b>>c>>d; qiude(a,b,c,d); cout<<endl; } cout<<"Over.\n"; return 0;}