void main()
{
float a,b,c,x1,x2;
cout<<"请输入方程的3个系数a b c \n";
cin>>a>>b>>c;
x1=(-b+sqrt(b*b-4*a*c))/2*a;
x2=(-b-sqrt(b*b-4*a*c))/2*a;
if(b*b-4*a*c<0)
cout<<"无实根!\n";
do{
x0=(x1*f(x2)-x2*f(x1))/(f(x2)-f(x1));
if(f(x0)*f(x1)>0)
x1=x0;
else
x2=x0;}
while(fabs(f(x0))>=1e-5);
cout<<"x="<<x0<<endl;
}
S7_1
#include<iostream.h>
int prime(int x)
S2_1
#include<iostream>
using namespace std;
void main()
{
float a,b,c;
cout<<"input a b c\n";
cin>>a>>b>>c;
if((a+b<c)||(b+c<a)||(a+c<b))
cout<<"Not Triangle\n";
float result;
int flag=0;
cout<<"请输入简单的运算式：\n";
cin>>a1>>oper>>a2;
switch(oper)
{
case'+':
result=a1+a2;
break;
case'-':
result=a1-a2;
break;
case'*':
result=a1*a2;
for(x=a;;x++)
if(x%a==0&&x%b==0&&x%c==0)
break;
cout<<x<<endl;
}
S4_5
#include<iostream.h>
void main()
{
int a;
for(a=100;a<=200;a++)
{
for(int b=2;b<a;b++)
if(a%b==0)
while(n%2!=0||n<6);
for(int i=2;i<n/2;i++)
{if(prime(i)==1&&prime(n-i)==1)
cout<<n<<'='<<i<<'+'<<n-i<<'\n';
}
cout<<endl;
}
S7_4
#include<math.h>
float f(float x)
{float y;
y=x*x+3*x-4;
return y;}
float df( float x)
{float y;
y=2*x+3;
return y;
}
void main()
{
float x0,x1;
x1=0;
do{
x0=x1;
x1=x0-f(x0)/df(x0);}
break;
default:
cout<<"输入错误的运算符!\n";
flag=1;
}
if(flag==0)
cout<<a1<<oper<<a2<<"="<<result<<endl;
}
S2_4
#include<iostream>
#include<math.h>
using namespace std;
cout<<"请输入初值x1和x2: ";
cin>>x1>>x2;}while(f(x1)*f(x2)>0);
do{
x0=(x1+x2)/2;
if(f(x0)*f(x1)>0)
x1=x0;
else
x2=x0;}
while(fabs(f(x0))>=1e-5);
cout<<"x="<<x0<<endl;
{for(int i=2;i<num/2;i++)
if(num%i==0)
return 0;
return 1;
}void main()
{
int n;
cout<<"请输入一个整数n: ";
cin>>n;
for(int i=2;i<n/2;i++)
{if(n%i==0&&prime(i)==1)
cout<<i<<'\t';
}
cout<<endl;
}
S7_3
#include<iostream.h>
int prime(int a)
{for(int i=2;i<a/2;i++)
if(a%i==0)
return 0;
return 1;
}
void main()
{int n;
do{cout<<"输入一个不小于6的偶数：";
cin>>n;}
for(c=1;c<=36;c++)
if(a+b+c==36&&a*4+b*2+c/2==36&&c%2==0)
cout<<"男人"<<a<<'\n'<<"女人"<<b<<'\n'<<"小孩"<<c<<endl;
}
S3_5_1
#include<iostream.h>
void main()
{
int a;
{
cout<<"Input x :";
cin>>x;
double y1,y2=x;
do{
y1=y2;
y2=2.0/3.0*y1+x/(3.0*y1*y1);
}while(fabs(y1-y2)>=1e-5);
cout <<"y="<<y2<<endl;
return 0;
}
S5_4
#include<iostream.h>
while(t=a%b)
{
a=b;
b=t;
}
cout<<"最大公约数："<<b<<endl;
cout<<"最小公倍数："<<x/b<<endl;
}
S4_2
#include<iostream.h>
void main()
{
int a, b,c;
cout<<"Input three number:";
cin>>a>>b>>c;
cin>>a;
while(a)
{b=a%10;
c=c+b;
a=a/10;}
cout<<c<<endl;
}
S4_1
#include<iostream.h>
void main()
{
int a,b;
int x,t;
cout<<"请输入两个正整数：";
cin>>a>>b;
x=a*b;
if(a<b)
{
t=a;a=b;b=t;}
a1=(b/10)%10;
a0=b%10;
if(b==a0*a0*a0+a1*a1*a1+a2*a2*a2)
cout<<b<<'\t';
}
}
S3_4
#include<iostream.h>
void main()
{
int a,b,c;
for(a=1;a<=36;a++)
for(b=1;b<=36;b++)
void main()
{
float x;
cout<<"Input x :";