C++第七章
2015-06-22 18:12
561 查看
1、
#include <iostream>
#include <cmath>
using namespace std;
int main()
{double a,b,c,s,area;
cout<<"please input a,b,c:";
cin>>a>>b>>c;
if (a+b<=c)
cerr<<"a+b<=c,error!"<<endl;
else if(b+c<=a)
cerr<<"b+c<=a,error!"<<endl;
else if (c+a<=b)
cerr<<"c+a<=b,error!"<<endl;
else
{s=(a+b+c)/2;
area=sqrt(s*(s-a)*(s-b)*(s-c));
cout<<"area="<<area<<endl;}
return 0;
}
2、
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{float a[5];
cout<<"input data:";
for(int i=0;i<5;i++)
cin>>a[i];
cout<<setiosflags(ios::fixed)<<setprecision(2);
for(int i=0;i<5;i++)
cout<<setw(10)<<a[i]<<endl;
return 0;
}
3、
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
for(int n=1;n<8;n++)
cout<<setw(20-n)<<setfill(' ')<<" " //nm
<<setw(2*n-1)<<setfill('B')<<"B"<<endl;
return 0;
}
4、
#include <iostream>
#include <stdlib.h>
#include <fstream>
using namespace std; //VC++ 6.0要此行
//fun1函数从键盘输入20个整数,分别存放在两个磁盘文件中
void fun1()
{int a[10];
ofstream outfile1("f1.dat"),outfile2("f2.dat"); //分别定义两个文件流对象
if(!outfile1) //检查打开f1.dat是否成功
{cerr<<"open f1.dat error!"<<endl;
exit(1);
}
if(!outfile2) //检查打开f2.dat是否成功
{cerr<<"open f2.dat error!"<<endl;
exit(1);
}
cout<<"enter 10 integer numbers:"<<endl;
for(int i=0;i<10;i++) //输入10个数存放到f1.dat文件中
{cin>>a[i];
outfile1<<a[i]<<" ";}
cout<<"enter 10 integer numbers:"<<endl;
for(int i=0;i<10;i++) //输入10个数存放到f2.dat文件中
{cin>>a[i];
outfile2<<a[i]<<" ";}
outfile1.close(); //关闭f1.dat文件
outfile2.close(); //关闭f2.dat文件
}
//从f1,dat读入10个数,然后存放到f2.dat文件原有数据的后面
void fun2()
{ifstream infile("f1.dat"); //f1.dat作为输入文件
if(!infile)
{cerr<<"open f1.dat error!"<<endl;
exit(1);
}
ofstream outfile("f2.dat",ios::app);
//f2.dat作为输出文件,文件指针指向文件尾,向它写入的数据放在原来数据的后面
if(!outfile)
{cerr<<"open f2.dat error!"<<endl;
exit(1);
}
int a;
for(int i=0;i<10;i++)
{infile>>a; //磁盘文件f2.dat读入一个整数
outfile<<a<<" "; //将该数存放到f2.dat中
}
infile.close();
outfile.close();
}
//从f2.dat中读入20个整数,将它们按从小到大的顺序存放到f2.dat
void fun3()
{ifstream infile("f2.dat"); //定义输入文件流infile,以输入方式打开f2.dat
if(!infile)
{cerr<<"open f2.dat error!"<<endl;
exit(1);
}
int a[20];
int i,j,t;
for(i=0;i<20;i++)
infile>>a[i]; //从磁盘文件f2.dat读入20个数放在数组a中
for(i=0;i<19;i++) //用起泡法对20个数排序
for(j=0;j<19-i;j++)
if(a[j]>a[j+1])
{t=a[j];a[j]=a[j+1];a[j+1]=t;}
infile.close(); //关闭输入文件f2.dat
ofstream outfile("f2.dat",ios::out);
// f2.dat作为输出文件,文件中原有内容删除
if(!outfile)
{cerr<<"open f2.dat error!"<<endl;
exit(1);}
cout<<"data in f2.dat:"<<endl;
for( i=0;i<20;i++)
{outfile<<a[i]<<" "; //向f2.dat输出已排序的20个数
cout<<a[i]<<" ";} //同时输出到显示器
cout<<endl;
outfile.close();
}
int main()
{fun1(); //分别调用3个函数
fun2();
fun3();
return 0;
}
5、
#include <iostream>
#include <fstream>
using namespace std;
struct staff
{int num;
char name[20];
int age;
double pay;
};
int main()
{staff staf[7]={2101,"Li",34,1203,2104,"Wang",23,674.5,2108,"Fun",54,778,
3006,"Xue",45,476.5,5101,"Ling",39,656.6},staf1;
fstream iofile("staff.dat",ios::in|ios::out|ios::binary);
if(!iofile)
{cerr<<"open error!"<<endl;
//abort(void);
}
int i,m,num;
cout<<"Five staff :"<<endl;
for(i=0;i<5;i++)
{cout<<staf[i].num<<" "<<staf[i].name<<" "<<staf[i].age<<" "<<staf[i].pay<<endl;
iofile.write((char *)&staf[i],sizeof(staf[i]));}
cout<<"please input data you want insert:"<<endl;
for(i=0;i<2;i++)
{cin>>staf1.num>>staf1.name>>staf1.age>>staf1.pay;
iofile.seekp(0,ios::end);
iofile.write((char *)&staf1,sizeof(staf1));}
iofile.seekg(0,ios::beg);
for(i=0;i<7;i++)
{iofile.read((char *)&staf[i],sizeof(staf[i]));
cout<<staf[i].num<<" "<<staf[i].name<<" "<<staf[i].age<<" "<<staf[i].pay<<endl;
}
bool find;
cout<<"enter number you want search,enter 0 to stop.";
cin>>num;
while(num)
{find=false;
iofile.seekg(0,ios::beg);
for(i=0;i<7;i++)
{iofile.read((char *)&staf[i],sizeof(staf[i]));
if(num==staf[i].num)
{m=iofile.tellg();
cout<<num<<" is No."<<m/sizeof(staf1)<<endl;
cout<<staf[i].num<<" "<<staf[i].name<<" "<<staf[i].age<<" "<<staf[i].pay<<endl;
find=true;
break;
}
}
if(!find)
cout<<"can't find "<<num<<endl;
cout<<"enter number you want search,enter 0 to stop.";
cin>>num;
}
iofile.close();
return 0;
}
6、
#include <iostream>
#include <strstream>
using namespace std;
struct student
{int num;
char name[20];
double score;
};
int main()
{student stud[3]={1001,"Li",78,1002,"Wang",89.5,1004,"Fun",90},stud1[3];
char c[50];
int i;
ostrstream strout(c,50);
for(i=0;i<3;i++)
strout<<stud[i].num<<" "<<stud[i].name<<" "<<st
4000
ud[i].score<<" ";
strout<<ends;
cout<<"array c:"<<endl<<c<<endl<<endl;
istrstream strin(c,50);
for(i=0;i<3;i++)
strin>>stud1[i].num>>stud1[i].name>>stud1[i].score;
cout<<"data from array c to array stud1:"<<endl;
for(i=0;i<3;i++)
cout<<stud1[i].num<<" "<<stud1[i].name<<" "<<stud1[i].score<<endl;
cout<<endl;
return 0;
}
#include <iostream>
#include <cmath>
using namespace std;
int main()
{double a,b,c,s,area;
cout<<"please input a,b,c:";
cin>>a>>b>>c;
if (a+b<=c)
cerr<<"a+b<=c,error!"<<endl;
else if(b+c<=a)
cerr<<"b+c<=a,error!"<<endl;
else if (c+a<=b)
cerr<<"c+a<=b,error!"<<endl;
else
{s=(a+b+c)/2;
area=sqrt(s*(s-a)*(s-b)*(s-c));
cout<<"area="<<area<<endl;}
return 0;
}
2、
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{float a[5];
cout<<"input data:";
for(int i=0;i<5;i++)
cin>>a[i];
cout<<setiosflags(ios::fixed)<<setprecision(2);
for(int i=0;i<5;i++)
cout<<setw(10)<<a[i]<<endl;
return 0;
}
3、
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
for(int n=1;n<8;n++)
cout<<setw(20-n)<<setfill(' ')<<" " //nm
<<setw(2*n-1)<<setfill('B')<<"B"<<endl;
return 0;
}
4、
#include <iostream>
#include <stdlib.h>
#include <fstream>
using namespace std; //VC++ 6.0要此行
//fun1函数从键盘输入20个整数,分别存放在两个磁盘文件中
void fun1()
{int a[10];
ofstream outfile1("f1.dat"),outfile2("f2.dat"); //分别定义两个文件流对象
if(!outfile1) //检查打开f1.dat是否成功
{cerr<<"open f1.dat error!"<<endl;
exit(1);
}
if(!outfile2) //检查打开f2.dat是否成功
{cerr<<"open f2.dat error!"<<endl;
exit(1);
}
cout<<"enter 10 integer numbers:"<<endl;
for(int i=0;i<10;i++) //输入10个数存放到f1.dat文件中
{cin>>a[i];
outfile1<<a[i]<<" ";}
cout<<"enter 10 integer numbers:"<<endl;
for(int i=0;i<10;i++) //输入10个数存放到f2.dat文件中
{cin>>a[i];
outfile2<<a[i]<<" ";}
outfile1.close(); //关闭f1.dat文件
outfile2.close(); //关闭f2.dat文件
}
//从f1,dat读入10个数,然后存放到f2.dat文件原有数据的后面
void fun2()
{ifstream infile("f1.dat"); //f1.dat作为输入文件
if(!infile)
{cerr<<"open f1.dat error!"<<endl;
exit(1);
}
ofstream outfile("f2.dat",ios::app);
//f2.dat作为输出文件,文件指针指向文件尾,向它写入的数据放在原来数据的后面
if(!outfile)
{cerr<<"open f2.dat error!"<<endl;
exit(1);
}
int a;
for(int i=0;i<10;i++)
{infile>>a; //磁盘文件f2.dat读入一个整数
outfile<<a<<" "; //将该数存放到f2.dat中
}
infile.close();
outfile.close();
}
//从f2.dat中读入20个整数,将它们按从小到大的顺序存放到f2.dat
void fun3()
{ifstream infile("f2.dat"); //定义输入文件流infile,以输入方式打开f2.dat
if(!infile)
{cerr<<"open f2.dat error!"<<endl;
exit(1);
}
int a[20];
int i,j,t;
for(i=0;i<20;i++)
infile>>a[i]; //从磁盘文件f2.dat读入20个数放在数组a中
for(i=0;i<19;i++) //用起泡法对20个数排序
for(j=0;j<19-i;j++)
if(a[j]>a[j+1])
{t=a[j];a[j]=a[j+1];a[j+1]=t;}
infile.close(); //关闭输入文件f2.dat
ofstream outfile("f2.dat",ios::out);
// f2.dat作为输出文件,文件中原有内容删除
if(!outfile)
{cerr<<"open f2.dat error!"<<endl;
exit(1);}
cout<<"data in f2.dat:"<<endl;
for( i=0;i<20;i++)
{outfile<<a[i]<<" "; //向f2.dat输出已排序的20个数
cout<<a[i]<<" ";} //同时输出到显示器
cout<<endl;
outfile.close();
}
int main()
{fun1(); //分别调用3个函数
fun2();
fun3();
return 0;
}
5、
#include <iostream>
#include <fstream>
using namespace std;
struct staff
{int num;
char name[20];
int age;
double pay;
};
int main()
{staff staf[7]={2101,"Li",34,1203,2104,"Wang",23,674.5,2108,"Fun",54,778,
3006,"Xue",45,476.5,5101,"Ling",39,656.6},staf1;
fstream iofile("staff.dat",ios::in|ios::out|ios::binary);
if(!iofile)
{cerr<<"open error!"<<endl;
//abort(void);
}
int i,m,num;
cout<<"Five staff :"<<endl;
for(i=0;i<5;i++)
{cout<<staf[i].num<<" "<<staf[i].name<<" "<<staf[i].age<<" "<<staf[i].pay<<endl;
iofile.write((char *)&staf[i],sizeof(staf[i]));}
cout<<"please input data you want insert:"<<endl;
for(i=0;i<2;i++)
{cin>>staf1.num>>staf1.name>>staf1.age>>staf1.pay;
iofile.seekp(0,ios::end);
iofile.write((char *)&staf1,sizeof(staf1));}
iofile.seekg(0,ios::beg);
for(i=0;i<7;i++)
{iofile.read((char *)&staf[i],sizeof(staf[i]));
cout<<staf[i].num<<" "<<staf[i].name<<" "<<staf[i].age<<" "<<staf[i].pay<<endl;
}
bool find;
cout<<"enter number you want search,enter 0 to stop.";
cin>>num;
while(num)
{find=false;
iofile.seekg(0,ios::beg);
for(i=0;i<7;i++)
{iofile.read((char *)&staf[i],sizeof(staf[i]));
if(num==staf[i].num)
{m=iofile.tellg();
cout<<num<<" is No."<<m/sizeof(staf1)<<endl;
cout<<staf[i].num<<" "<<staf[i].name<<" "<<staf[i].age<<" "<<staf[i].pay<<endl;
find=true;
break;
}
}
if(!find)
cout<<"can't find "<<num<<endl;
cout<<"enter number you want search,enter 0 to stop.";
cin>>num;
}
iofile.close();
return 0;
}
6、
#include <iostream>
#include <strstream>
using namespace std;
struct student
{int num;
char name[20];
double score;
};
int main()
{student stud[3]={1001,"Li",78,1002,"Wang",89.5,1004,"Fun",90},stud1[3];
char c[50];
int i;
ostrstream strout(c,50);
for(i=0;i<3;i++)
strout<<stud[i].num<<" "<<stud[i].name<<" "<<st
4000
ud[i].score<<" ";
strout<<ends;
cout<<"array c:"<<endl<<c<<endl<<endl;
istrstream strin(c,50);
for(i=0;i<3;i++)
strin>>stud1[i].num>>stud1[i].name>>stud1[i].score;
cout<<"data from array c to array stud1:"<<endl;
for(i=0;i<3;i++)
cout<<stud1[i].num<<" "<<stud1[i].name<<" "<<stud1[i].score<<endl;
cout<<endl;
return 0;
}
相关文章推荐
- <Effective C++>读书笔记-4
- C++内联函数、函数模板之于头文件
- c++指针和引用
- C语言回顾(七、多重指针,argc,argv,动态内存分配,void指针,const)——iOS开发基础
- 无向图 深度优先遍历 c语言实现
- ACM输入输出--多组测试用例--C、C++、Java
- 解释int a=9;printf("%d,%d",a,a++)?输出情况
- c++中string类的详解
- c,c++,java用户自定义标识符命名规则比较
- 2 通过JNI混合使用Java和C++ -----> 访问数组
- C++静态局部对象
- C语言源字符集与执行字符集
- 两个乒乓球队进行比赛,各出3人。
- 无向图 广度优先遍历 c语言实现
- C语言回顾(六、基类型,数组指针,字符串指针,函数指针,文字常量区)——iOS开发基础
- Eclipse+CDT+Cygwin进行C&C++开发
- C++中的C_str()函数用法
- 标准C++库中的异常类
- c++操作符重载
- vc++6.0错误