//P85_1floatarea(floata,floatb,floatc);intprime(intx);voidprintchar(charch,intn);//P85_2#include<iostream.h>intgys(intx,inty){inti;for(i=x;i>=1;i--)if(x%i==0&&y%i==0)returni;}intgbs(intx,inty){inti;for(i=x;i<=x*y;i++)if(i%x==0&&i%y==0)returni;}voidmain(){intx,y;cin>>x>>y;cout<<"最大公约数="<<gys(x,y)<<endl;cout<<"最小公倍数="<<gbs(x,y)<<endl;}//P85_4#include<iostream.h>#include<math.h>intprime(intx){inti;for(i=2;i<=sqrt(x);i++)if(x%i==0)return0;return1;}//P85_3#include<iostream.h>#include<math.h>floatarea(floata,floatb,floatc){floatl,s;l=(a+b+c)/2;s=sqrt(l*(l-a)*(l-b)*(l-c));returns;}voidmain(){floatx1,y1,x2,y2,x3,y3,x4,y4,x5,y5,a12,a13,a23,a14,a34,a15,a45,s;cout<<"输入五边形五个顶点的坐标\n";cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4>>x5>>y5;a12=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));a23=sqrt((x2-x3)*(x2-x3)+(y2-y3)*(y2-y3));a13=sqrt((x1-x3)*(x1-x3)+(y1-y3)*(y1-y3));a14=sqrt((x1-x4)*(x1-x4)+(y1-y4)*(y1-y4));a34=sqrt((x3-x4)*(x3-x4)+(y3-y4)*(y3-y4));a15=sqrt((x1-x5)*(x1-x5)+(y1-y5)*(y1-y5));a45=sqrt((x4-x5)*(x4-x5)+(y4-y5)*(y4-y5));s=area(a12,a13,a23)+area(a13,a14,a34)+area(a14,a15,a45);cout<<"五边形的面积="<<s<<'\n';}//P85_4voidmain(){inti;for(i=3;i<999;i+=2)if(prime(i)&&prime(i+2))cout<<i<<'\t'<<i+2<<'\n';}//P85_6#include<iostream.h>#include<math.h>intprime(intx){inti;for(i=2;i<=sqrt(x);i++)if(x%i==0)return0;return1;}intreverse(intx){inta,t=0;while(x!=0){a=x%10;t=t*10+a;x=x/10;}returnt;}voidmain(){inti,r;for(i=100;i<=999;i++){r=reverse(i);if(prime(i)&&prime(r))cout<<i<<'\t';}}voidmain(){floata,b,c,d,x1,x2;cin>>a>>b>>c;d=delta(a,b,c);if(d!=-1){x1=(-b+d)/(2*a);x2=(-b-d)/(2*a);cout<<"方程的根："<<x1<<'\t'<<x2<<'\n';}elsecout<<"方程没有实根\n";}//P85_5#include<iostream.h>voidprintstar(intn){inti;for(i=1;i<=n;i++)cout<<"*";}voidmain(){inti