Why is this program not working ... Can any one help ?

Question

// program to accept digits of a number and display the number as one.
#include<iostream>
using namespace std;
int main()
{
char t[100],a;
int m=0;
cout<<"Enter(press * after the last digit to stop entering.): ";
while(a!='*')
{
cin>>a;
t[m]=a;
m++;
}
int c;
c=t[0]*100+t[1]*10+t[2];
cout<<c;
}

Answer 1

I guess you already know cin >> intVar, or cin >> stringVar and use stoi() to convert string to integer, then I assume you must have a reason to get input that way, can you explain that?

Answer 2

If you check out the ascii table
https://www.asciitable.com/

You'll see that the numbers are in the range 48 - 57.

If the user enters a 3 for example, what is actually stored is 51

If the user enters 345
51 52 53 is stored.

t[0]*100+t[1]*10+t[2];
You are using those numbers here to do the math
51 * 100 + 52 * 10 + 53 = 5673

You'll have to convert those numbers to the correct value by subtracting '0', which equals 48 from these numbers
(t[0]-'0')*100 + (t[1]-'0')*10 + (t[2]-'0');

(51 - 48)*100 + (52 - 48) * 10 + (53 - 48)
=
(3 * 100) + (4 * 10) + (5)
=
345

Also a is uninitialized, in the event that a starts out with a '*' the loop isn't even entered.
I recommend replacing the while loop with a do while loop instead or initializing a with anything besides '*'

Answer 3

Well, it would help If you tell us what excatly error message do you get or what does not work.

Answer 4

Their is no error it just won't work correctly.

Answer 5

I'm not sure what the program does do (I did read the description on top). What I would probbably do is use Switch and Cases instead of while(a!="*"). So it would look like:

switch(a)
{
case('*')
cin>>a;
t[m] = a;
m++;
break;
}

You can check my code and scroll down for some examples:

https://code.sololearn.com/cyqTln6peslH/?ref=app

Answer 6

Ok thanks

Answer 7

I guess the main problem is that t is a char and c is a int, then
the line
c=t[0]*100+t[1]*10+t[2];
will give a weird result.
You can solve it by declaring t as int, and then in the loop change the line
t[m]=a;
to
t[m]=(int) a;

Answer 8

But even though I use the do while loop I must set a condition by which the loop may exit.

Answer 9

Which you can do ?

do
{
cin>>a;
t[m]=a;
m++;
}while(a!='*');

Answer 10

Thanks dude. I agree.