if statements

[mandarin]

Hello

As I write this I realise that my question is most likely not specific to C++, but I encountered the "problem" while writing C++ with openFrameworks.

My question is simple: Why do these two if statements produce different results?

Statement 1 (doesn't work):
if (exploded) {
age += explodeRate;
if (age > timetodie) { exploded = false; }
}

Statement 2 (works):
if (exploded) {
if (age < timetodie) { age += explodeRate; }
else { exploded = false; }
}

I use the variable age to help calculate the size of an explosion. With statement 1 the explosions will forever expand, and with statement 2 they'll stop when I want them to stop.

[AngelHoof]

Errr.. Read that wrong.. Nevermind

[moorecm]

http://www.cplusplus.com/doc/tutorial/control/

[crazzyguy101]

In Statement 1, if exploded is true, age is always incremented by explodeRate, whereas in Statement 2, age is only incremented if it less than timetodie.

In Statement 1, if age == timetodie, exploded is not altered.

[z05DSL3A]

In Statement 1, if age == timetodie, exploded is not altered.

In Statement 2, if age == timetodie, exploded is not altered.

[crazzyguy101]

@Grey Wolf : huh ?
Statemet 1 :

if ( age > timetodie )         // if age == timetodie, it evaluates to false
{
       exploded = false;     // since it is false, exploded is not altered.
}

Statment 2

if  ( age < timetodie )       // if age == timetodie, it evaluates to false and else is executed
       ......
else
{
       exploded = false;    // exploded IS altered
}

[sparticus37]

@crazyguy101

you are confusing the == operator with the operators < ,> <= ,>=

with statement 1 assuming age is 1 and time to die is 1, because 1 is not greater than 1 the condition evaluates to false , and it skips the body of control statement.
however if he said something like

if( age >= timetodie) 
{
       return false;
}

then what you said would be true becasuse 1 is greater than or equal to 1


@mandarin
looking at your problem ,what are your test values for age, timetodie, and explodeRate

[z05DSL3A]

crazzyguy101 wrote:

Grey Wolf : huh ?

Long day (week) at work = misreading and misunderstanding. :0)