A composite primary key<span> is a set of several primary </span>keys<span> that, together, uniquely identifies each record.</span>
Primary keys are used as identifiers of composite entities. In this case each primary key combination is allowed only once in the *:* relationship.
Other case where primary keys are used is as identifiers of weak entities, where the weak entity has a strong identifying relationship with the parent entity.
Answer:
dataFile << salary;
Explanation:
To write salary to a file (payroll.dat) using ofstream, you make use of the following instruction:
<em>ofstream dataFile;
</em>
<em>myfile.open ("payroll.dat");
</em>
<em>myfile <<salary;
</em>
<em>myfile.close();</em>
<em />
This line creates an instance of ofstream
<em>ofstream dataFile;
</em>
This line opens the file payroll.dat
<em>myfile.open ("payroll.dat");
</em>
This is where the exact instruction in the question is done. This writes the value of salary to payroll.dat
<em>myfile <<salary;
</em>
This closes the opened file
<em>myfile.close();</em>
<em />
<em />
Answer:
int state[] = new int[8];
Answer:
#include <iostream>
using namespace std;
class Str{ ///baseclass
public :
string super_str;
string getStr()
{
return super_str;
}
void setStr(string String)
{
super_str=String;
}
};
class str : public Str{ //inheriting Str publicly
public :
string sub_str;
string getstr()
{
return sub_str;
}
void setstr(string String)
{
sub_str=String;
}
bool notstartswith()
{
int n=sub_str.length(); //to find length of substr
bool flag=false;
for(int i=0;i<n;i++) //Loop to check beginning of Str
{
if(super_str[i]!=sub_str[i])
{
flag=true;
break;
}
}
return flag;
}
};
int main()
{
str s; //object of subclass
s.setStr("Helloworld");
s.setstr("Hey");
if(s.notstartswith()==1) //checking if str is substring of Str
cout<<"Str does not start with str";
else
cout<<"Str starts with str";
return 0;
}
OUTPUT :
Str does not start with str
Explanation:
Above program is implemented the way as mentioned. for loop is being used to check the beginning of the str starts with substring or not.