Getting warnings in my C++ variables

[Diana Magers]

Trying to understand my warnings on 'double' to 'const int' possible loss of data and truncation from 'double' to 'float'.

Not sure where I went wrong.........Need help understanding.

Warning 1 warning C4244: 'initializing' : conversion from 'double' to 'const int', possible loss of data
Warning 2 warning C4305: 'initializing' : truncation from 'double' to 'float'

This is what I have for my variables:

//input variables

float SLICES = 0.0;
int const PI = 3.14;
float SLICE_AREA = 14.13;
float radius;

Please help me understand where I went wrong. I am a beginner.

[Wazzak]

Truncation is when the fractional part of a floating-point literal/value is removed so it's compatible with a integral type.

Edit:

Here's what's happening: The int type can only hold whole numbers. The float/double types can hold whole & fractional numbers (numbers such as 4.3). When a floating point number (a number with a fractional counterpart) is assigned to a variable of type int, the compiler will notice and truncate the fractional counterpart. Here's an example:

int Integer(0);
float Real(1.2F); // The 'F' denotes the literal as a 4-byte float.

Integer = Real; // Truncation here. 

In the above code, when Integer is assigned to Real, the .2 of Real's value is removed (truncation). The resulting value is compatible with int.

_Wazzak

[hanst99]

In other words, you just defined PI to be equal to 3.

[Umair Bukhari]

can we declare double and float at the same time?

[nishantbhambhoria]

guys need help in running this code.dont know why it is getting struck??
//program to insert data in a sorted file.....
#include<fstream.h>
#include<stdio.h>
#include<conio.h>

class stu
{ int rollno;
char name[20];
int Class;
float marks;
char grade;

public:
void getdata()
{ cout<<"rollno:";
cin>>rollno;
cout<<"name:";
cin>>name;
cout<<"Class:";
cin>>Class;
cout<<"marks:";
cin>>marks;
if(marks>=75) grade='A';
else if(marks>=60) grade='B';
else if(marks>=50) grade='C';
else if(marks>=40) grade='D';
else grade='E';
}

void putdata()
{ cout<<"rollno"<<rollno<<"\t name:"<<name
<<"\n marks:"<<marks<<"\t Grade:"<<grade<<endl;
}
int getrno()
{return rollno;}

}s1,stud;


void main()
{ clrscr();
ifstream fi("stu.dat",ios::in);
ofstream fo("temp.dat",ios::out);
char last ='y';
cout<<"enter details of student whose record is to be inserted\n";
s1.getdata();
while(!fi.eof())
{ fi.read((char*)&stud,sizeof(stud));
if(s1.getrno()<=stud.getrno())
{fo.write((char*)&s1,sizeof(s1)) ;
last='n';
break;
}
else
fo.write((char*)&stud,sizeof(stud));
}

if(last=='y')
fo.write((char*)&s1,sizeof(s1));

else if(!fi.eof())
{
while(!fi.eof())
{ fi.read((char*)&stud,sizeof(stud));
fo.write((char*)&stud,sizeof(stud));
}
}


fi.close();
fo.close();
remove("stu.dat");
rename("temp.dat","stu.dat");
fi.open("stu.dat",ios::in);
cout<<"file now contains\n";
while(!fi.eof())
{fi.read((char*)&stud,sizeof(stud));
if(fi.eof())break;
stud.putdata();
}

fi.close();
getch();
}

[Moschops]

Start a new thread with your question, use [code] tags, and get a compiler that's not 15 years old.