Question

两道简单C++的题目不会做，高手们快来帮忙

如题

Answer 1

第一题
==============================
#include<iostream>
using namespace std;
void main()
{
float num1,num2;
char str;
cout<<"请输入操作数1，运算符op,操作数2:"<<endl;
cin>>num1>>str>>num2;
switch (str)
{
case '+':cout<<num1<<str<<num2<<"="<<num1+num2<<endl;break;
case '-':cout<<num1<<str<<num2<<"="<<num1-num2<<endl;break;
case '*':cout<<num1<<str<<num2<<"="<<num1*num2<<endl;break;
case '/':cout<<num1<<str<<num2<<"="<<num1/num2<<endl;break;
default:cout<<"input wrong!"<<endl;break;
}
}

==============================
第二题：
===============================
#include<iostream>
#include<cmath>
using namespace std;
void main()
{
float a,b,c;
cout<<"Input a,b and c:"<<endl;
cin>>a>>b>>c;
cout<<a<<"X^2+"<<b<<"X+"<<c<<"=0 "<<endl;
if(b*b<4*a*c)
cout<<"NO solution!"<<endl;
else
{

cout<<"the root of the equation are:"<<endl;
cout<<"X1="<<(-b+sqrt(b*b-4*a*c))/(2*a)<<endl;
cout<<"X2="<<(-b-sqrt(b*b-4*a*c))/(2*a)<<endl;

}

}

=============================

Answer 2

//第一题

#include "iostream"
using namespace std;
int main()
{
double num1,num2,num=0;
char op;
cout<<"请输入操作数1 运算符op 操作数2\n";
cin>>num1>>op>>num2;
switch(op)
{
case '+': num=num1+num2;break;
case '-':num=num1-num2;break;
case '*':num=num1*num2;break;
case '/':num=num1/num2;break;
default:break;
}
cout<<endl<<num1<<op<<num2<<"="<<num<<endl;
return 0;
}

//第二题
#include <math.h>
#include <iostream>
using namespace std;
int main()
{

double a,b,c,s;
cout<<"请输入:a b c\n";
cin>>a>>b>>c;
s=b*b-4*a*c;
if(s==0)
{
cout<<"\n只有一个解\n";
cout<<"x1=x2="<<(-b)/(2*a)<<endl;
}
else if(s>0)
{
cout<<"\n有两个解\n";
cout<<"x1="<<(-b+sqrt(s))/(2*a)<<endl;
cout<<"x2="<<(-b-sqrt(s))/(2*a)<<endl;
}
else
cout<<"\n此方程无解\n";
return 0;
}

Answer 3

兄弟，上课是不是没认真听讲啊

Answer 4

闪……人