Question

Alchemista and fedep3 let's continue here

Answer 1

i hate it when the thread gets too long

Answer 2

here we go Alchemista..

Answer 3

ok

Answer 4

okay now it works thanks ill work with more options. hopefully by the end of today ima add meters to feet and backwards and kilometers to miles and backwards and farenheit to celsius and backwards..

Answer 5

Oh also alchemista can I add Choice 3 - Exit then would I sort of set return 0; for choice 3?

Answer 6

yes that would work.

Answer 7

case '3':
return 0;

Answer 8

do I need a break at the end too?

Answer 9

Also I think I should let you know why we are using single quotes around the numbers. What we are actually comparing with is the ASCII value of the numbers not the number itself.

Answer 10

no because you are already returning from the function.

Answer 11

oh okay and what is the ASCII value of numbers oh i have this weird table in my book so if I were to pick the option not 1 2 and 3 but a b and c instead of putting '1' i would put 'ASCII for a' ?

Answer 12

well 1 won't be ascii for a, but it certainly wont be ascii for '1'

Answer 13

http://www.asciitable.com/index/asciifull.gif

Answer 14

daang.. am i going to have to memorize all that?

Answer 15

no

Answer 16

nop

Answer 17

thats the point of the single quotes.

Answer 18

thats what I was trying to tell you, the reason we are using single quotes around the numbers.

Answer 19

It tells the C++ compiler we want the ascii value of '1' not 1 itself.

Answer 20

ohhh i see if we did not have them we'd have to put the actual ascii right?

Answer 21

* i mean if we didnt have quotes..

Answer 22

yes thats right!

Answer 23

okay good.. now i want to know what these stand for:
for ( ;; )

Answer 24

its an infinite loop.

Answer 25

ohh so until i select 3 (exit choice) i will keep getting that select option?

Answer 26

the for loop has three parts
the first is for declaring variables, the second is a condition, the third is a statement

Answer 27

but since we have no conditions it will just loop forever.

Answer 28

in the for u have

first the initialitation, then the condition and at last what u gonna do after u do the stament of the cicle

Answer 29

okay so it's like:
for (initiation;condition;what i will do) ?

Answer 30

for ( int i = 0; i < 10; i++ ) cout << i << endl;

Answer 31

thats an example

Answer 32

that will print the numbers from 0-9

Answer 33

okay.. i see

Answer 34

ill put in a more simple way the for its a while

so if u have
for(a;b;c) { d;} its a:

a;
while(b){
d;
c;
}

Answer 35

yes pretty much although there is a small difference in these two examples.

Answer 36

a is only in the scope of the for loop

Answer 37

in the while loop example a does not go out of scope after the while loop

Answer 38

yea thats true

Answer 39

okay guys i will be back in like 10 minutes let me add a couple of more converters to that..

Answer 40

thanks for the help ! =)

Answer 41

i g2g, sry! but if u want to practice more, there are some good problems here http://www.spoj.pl/problems/classical/sort=-6, the first ones are the ones that have been solved by more users, and are the easiest ones, gl!

Answer 42

u can google too more about c++

Answer 43

also most of the things we talked about were valid in C

Answer 44

except the stream operations

Answer 45

alchemista what is wrong here?

Answer 46

#include <iostream>

using namespace std;

int main () {
char choice;
float value;
cout << "Select choice:" << endl
<< "1) Kilometers -> Meters" << endl
<< "2) Meters -> Kilometers" << endl
<< "3) Feet -> Meters " << endl
<< "4) Exit" << end1;
for ( ;; ) {
cout << "Select: " << flush;
cin >> choice;
switch ( choice ) {
case '1':
cout << "Kilometers=" << flush;
cin >> value;
cout << value << " kilometers is " << value*1000.0 << " meters." << endl;
break;
case '2':
cout << "Meters=" << flush;
cin >> value;
cout << value << " meters is " << value/1000.0 << " kilometers." << endl;
break;
case '3':
cout<< "Feet=" << flush;
cin >> value;
cout << value << " feet is " << value*0.3048 << " meters." << end1;
case '4':
return 0;
default:
cout << "Unknown choice!" << endl;
}
}

}

Answer 47

it is underlining that end1; at the 4)Exit part..

Answer 48

you forgot the break again.

Answer 49

ohhh okay thanks

Answer 50

it still failed..

Answer 51

is it not compiling?

Answer 52

<< "4) Exit" << end1;

This end1; is being underlined as a mistake

Answer 53

one second

Answer 54

its endl the letter l as in leo the lion not 1

Answer 55

ohh wow haha! I see thanks! never noticed that..

Answer 56

does that mean endline?

Answer 57

yes of course

Answer 58

oh okay thanks if i have another question i will post it as a new thread.. Man you save me all over the place... with lin algebra and this too now i really appreciate ur help..