CODEWITHSUNDEEP
c++if-statement
Portaljacker
Portaljacker

Reputation: 3142

Will else-is resolve if the if statement above it is chosen?

In this set of statements:

if(robot1Count < 12) {
    robot1Count++;
}
else if(robot1Count < 24) {
    robot1Count++;
}
else if(robot1Count < 36) {
    robot1Count++;
}
else if(robot1Count < 48) {
    robot1Count++;
}
else {
    robot1Count = 0;
}

Imagine this is in an infinite loop, would this loop traverse from 0 to 48, change to 0. The thing I'm wondering is if the first block is executed, would all the following blocks be ignored? Or should I change the second to else if(robot1Count < 24 && robot1Count >= 12) ? Or does that not matter?

Upvotes: 0

Views: 113

Answers (5)

jason
jason

Reputation: 241651

The thing I'm wondering is if the first block is executed, would all the following blocks be ignored?

Yes, they will all be ignored. The conditions won't even be evaluated. But you know, you could have tested this yourself!

if(robot1Count < 12) {
    printf("< 12");
    robot1Count++;
}
else if(robot1Count < 24) {
    printf(">= 12 && < 24");
    robot1Count++;
}
else if(robot1Count < 36) {
    printf(">= 24 && < 36");
    robot1Count++;
}
else if(robot1Count < 48) {
    printf(">= 36 && < 48");
    robot1Count++;
}
else {
    printf(">= 48");
    robot1Count = 0;
}

And then you can see which messages are printed to the console and then you'd know and feel what is going on!

Upvotes: 7

nate_weldon
nate_weldon

Reputation: 2349

if the code above is in a infinite loop

example

int robot1Count = 0;
while (1 != 2) {

if(robot1Count < 12) {
    robot1Count++;
}
else if(robot1Count < 24) {
    robot1Count++;
}
else if(robot1Count < 36) {
    robot1Count++;
}
else if(robot1Count < 48) {
    robot1Count++;
}
else {
    robot1Count = 0;
}
}

in a loop this will increment to 48 and go back to 0

it will only hit robot1Count++ per single execution of the loop

Upvotes: 1

Jerry Coffin
Jerry Coffin

Reputation: 490178

Yes -- the if leg and the else leg of an if statement are mututally exclusive -- if the if leg executes the else does not (and vice versa).

Upvotes: 2

Oliver Charlesworth
Oliver Charlesworth

Reputation: 272537

This:

if (cond1)
    stuff1;
else if (cond2)
    stuff2;
else if (cond3)
    stuff3;
else
    stuff4;

is identical to this:

if (cond1) {
    stuff1;
}
else {
    if (cond2) {
        stuff2;
    }
    else {
        if (cond3) {
            stuff3;
        }
        else {
            stuff4;
        }
    }
}

Upvotes: 4

idish
idish

Reputation: 3260

Of course they will be ignored, unless you switch the "else if" to "if"

Upvotes: 1

Related Questions