第三周作业

例题2.1

/********************************
**功能：布尔类型使用列举**
********************************/
#include<iostream>
#include<iostream>
usingnamespacestd;

intmain()
{

charch;cout<<"pleaseinputacharacter:";cin>>ch;ch=ch>='a'&&ch<='z'?ch-'a'+'A':ch;cout<<"Theresultis:"<<ch<<endl;return0;}

例题2.2

/*********************************功能：赋值表达式语句的使用**********************************/#include<iostream>usingnamespacestd;intmain(){inta,b,c,d;a=4;b=a;a=5;c=d=6;c*=a;d%=a+b;cout<<"a="<<a<<endl<<"b="<<b<<endl<<"c="<<c<<endl<<"d="<<d<<endl;return0;}例题2.3#include<iostream>usingnamespacestd;intmain(){shorti,j,m,n;i=1000;j=1000;m=i+j;n=i*j;cout<<"m="<<m<<endl;cout<<"n="<<n<<endl;return0;}

例题2.4#include<iostream>usingnamespacestd;intmain(){inti=6,j,k;j=++i;k=i++;++i=1;cout<<"i="<<i<<endl<<"j="<<j<<endl<<"k="<<k<<endl;return0;}

例题2.5#include<iomanip>usingnamespacestd;intmain(){boolflag=true;cout<<flag<<endl;cout<<boolalpha<<flag<<endl;cout<<flag+5<<endl;flag=0;cout<<"执行语句flag=0;后flag的值为:"<<boolalpha<<flag<<endl;flag=0.0;cout<<"执行语句flag=0;后flag的值为:"<<boolalpha<<flag<<endl;return0;}

例题2.7

#include<iostream>usingnamespacestd;intmain(){intab,ac;doubleb=3.14;charc='A';ab=int(b);ac=int(c);cout<<"b="<<b<<endl;cout<<"ab="<<ab<<endl;cout<<"c="<<c<<endl;cout<<"ac="<<ac<<endl;return0;}

求三角形周长及面积

/**************任意给三边求周长l以及面积s*************/#include<iostream>#include<math.h>usingnamespacestd;intmain(){inta,b,c,l,p,s;cout<<"请输入a的长度:"<<endl;cin>>a;cout<<"请输入b的长度:"<<endl;cin>>b;cout<<"请输入c的长度:"<<endl;cin>>c;l=a+b+c;l/=2;p=l;s=sqrt(p*(p-a)*(p-b)*(p-c));cout<<"l="<<l<<endl;cout<<"s="<<s<<endl;return0;}

解一元二次方程

#include<iostream>#include<math.h>usingnamespacestd;intmain(){doublex1,x2,a,b,c,d;cout<<"输入方程x^2+bx+c=0中的a:";cin>>a;cout<<"输入方程x^2+bx+c=0中的b:";cin>>b;cout<<"输入方程x^2+bx+c=0中的c:";cin>>c;d=sqrt(b^2-4*a*c);if(d>0){x1=(-b+d)/(2*a);x2=(-b-d)/(2*a);cout<<"方程有两个根，且为：x1="<<x1<<",x2="<<x2<<endl;}if(d=0){x1=x2=(-b)/(2*a);cout<<"方程有两个根，且为:x1="<<x1<<",x2="<<x2<<endl;}if(d<0){cout<<"该方程无解!"<<endl;}return0;}

#include<iostream>usingnamespacestd;intmain(){chara[50],b[50];inti;cout<<"输入姓名拼音"<<endl;cin.get(a,50);cout<<"加密后"<<endl;for(i=0;i<50;i++){if(a[i]==0){break;}b[i]=a[i];b[i]=b[i]+5;cout<<b[i];}cout<<endl;return0;

}