Else statement condition error

[reon]

In the below code.. else statements didnt work correctly... the program is to add the positive and negative numbers... if we enter alphabets it will show the wrong entry ,, but thats not working.....

#include<iostream.h>
#include<conio.h>
class loops
{
int i;
int sum;
int sum2;
int num;
public:
void accept()
{
for(sum=num=i=0;i<3;i++)
    {
    cout<<"Enter a number : "<<endl;
    cin>>num;
    if(num>=0)
    sum=sum+num;
    else if(num<=0)
    sum2=sum2+num;
    else
    {
    cout<<"Wrong entry";    //its not working....(dont know wat to do)..
    }
    }
}
void display()
    {
    cout<<endl<<"The sum of positive numbers entered is : "<<sum;
    cout<<endl<<"The sum of negative numbers entered is : "<<sum2;
    }
};
void main()
{
clrscr();
loops l1;
l1.accept();
l1.display();
getch();
}

[RedSon]

This is because alphabits are actually represented by numeric values that map to a standard ascii table. So when a user types a letter your program casts that value to an int.

[reon]

ok fine!! is there any method to convert int to char ... i'm a beginner if u know how to convert ....pls give up more details....

This is because alphabits are actually represented by numeric values that map to a standard ascii table. So when a user types a letter your program casts that value to an int.

[RedSon]

Well, a brute force way is to check if your input variable is equivalent to all of the characters.

////////PSEUDOCODE////////
if (input == 'a' || input == 'b' || ... || input == 'z')
{
   //then a letter is input into your variable.
}
 

It might be easier to see if there is a library that will help you to support this type of input checking.

[reon]

ok thanx...

[reon]

Any more ideas except brute force ...

[horace1]

you have a couple of errors - the simple one was that you did not initiaialise sum2 to 0 so you negaive additions were wrong (local variables are not initialised by default). the other problem is dealing withfaulty input. if you attempt to read an int and you enter some faulty character the input fails and the character is left in the input stream. you have to clear the error condition and remove the faulty character before attempting to read again. try this

#include<iostream.h>
#include<conio.h>
class loops
{
int i;
int sum;
int sum2;
int num;
public:
void accept()
{
for(sum=sum2=num=i=0;i<3;i++)  //** zero sum2
    {
    cout<<"Enter a number : "<<endl;
    while(! (cin>>num))  // ** if input fail
       {
       cout<<"Wrong entry, reentry number ";    //its not working....(dont know wat to do)..
       cin.clear(); // ** clear error
         cin.ignore(1000,'\n');  // remove faulty chars from stream
       }
     if(num>=0)
           sum=sum+num;
     else if(num<=0)
         sum2=sum2+num;
      }
 
}
void display()
    {
    cout<<endl<<"The sum of positive numbers entered is : "<<sum;
    cout<<endl<<"The sum of negative numbers entered is : "<<sum2;
    }
};
 
int main()
{
//clrscr();
loops l1;
l1.accept();
l1.display();
getchar();getchar();
}
 

[reon]

Ur guided me as i think....
But one problem is i didnt understand that cin.clear and cin.ignore ...(is that a keyword like cin.getline(var,size)..)
you used while loop but didnt enter continue or break,, thats so confusing to me....
if u dont mind either explain that or post any links or something to refer...