C++经典编程例题(1)1、(已验证!)计算铁路运费。已知从甲地到乙地,每张票托运行李不超过50公斤时,按每公斤0.13元,超过50公斤,超过部分按每公斤0.2元计算。输入行李重量w,计算运费y.#include<iostream>usingnamespacestd;voidmain(){floatmoney=0,weight;cout<<"请输入货物重量(单位:千克):";cin>>weight;if(weight<0)cout<<”数据错误!”<<endl;if(weight<=50)money=weight*0.13;elseif(weight>50)money=50*0.13+(weight-50)*0.2;cout<<"\n总费用是:"<<money<<endl;}2、(已验证!)根据一元二次方程a*x*x+b*x+c=0求解方程。输入a、b、c的值,求x1、x2的实根.#include<iostream>#include<cmath>usingnamespacestd;voidmain(){doublea,b,c,p,x1,x2,D;cout<<"请输入3个数:"<<endl;cout<<"a=";cin>>a;cout<<"b=";cin>>b;cout<<"c=";cin>>c;cout<<"方程为:"<<a<<"x^2+"<<b<<"x+"<<c<<"=0"<<endl;D=b*b-4*a*c;if(D<0)cout<<"方程无解!"<<endl;if(D==0){p=-b/(2*a);x1=p+sqrt(D)/(2*a);cout<<"方程有两个相同的实根。"<<endl;cout<<"x1=x2="<<x1<<endl;}if(D>0){p=-b/(2*a);x1=p+sqrt(D)/(2*a);x2=p-sqrt(D)/(2*a);cout<<"方程有两个不同的实根。"<<endl;cout<<"x1="<<x1<<endl<<"x2="<<x2<<endl;}}3、(已验证!)分别使用for和while求n!.注解n!=1*2*3*...*n,n由键盘输入。For:#include<iostream>usingnamespacestd;voidmain(){inti,n,s;s=1;cout<<"inputn:";cin>>n;for(i=1;i<=n;i++)s=i*s;cout<<s<<endl;}While:#include<iostream>usingnamespacestd;voidmain(){inti,n,s;s=1;i=1;cout<<"inputn:";cin>>n;while(i<=n){s=i*s;++i;}cout<<s<<endl;}4、(已验证!)百钱买百鸡。1只公鸡5元,1只母鸡3元,3只小鸡1元,现有100元钱要买100只鸡,有什么解法。分别使用三重循环和二重循环来解.鸡翁,鸡婆,鸡雏各:12、4、84只鸡翁,鸡婆,鸡雏各:8、11、81只鸡翁,鸡婆,鸡雏各:4、18、78只鸡翁,鸡婆,鸡雏各:0、25、75只(1).三重循环:#include<iostream>usingnamespacestd;voidmain(){constintcock=20,hen=33,chicken=100;intc,h,ck;for(c=0;c<=cock;c++){for(h=0;h<=hen;h++){for(ck=0;ck<=chicken;ck++){if(((c+h+ck)==100)&&((c*5+h*3+ck/3)==100)&&((ck%3)==0))cout<<"鸡翁,鸡婆,鸡雏各:"<<c<<"、"<<h<<"、"<<ck<<"只"<<endl;}}}}(2).两重循环:#include<iostream>usingnamespacestd;voidmain(){intc,h,ck;for(h=0;h<33;h++)for(ck=0;ck<100;ck++...