If && not working

I have looked at every similar question i can find but i am scratching to work out why my if && stament isn't working.

if ((cEventStatus) && (ddayDif = 0)) {
        NSLog(@"upDateCountersWorking");
        [self upDateCountersWorking];

}else if ((cEventStatus) && (ddayDif > 0 )){
    NSLog(@"currentlyWorkingAddDays");
    [self currentlyWorkingAddDays:&ddayDif];

}else if ((!cEventStatus) && (ddayDif = 0)){
     NSLog(@"upDateCountersResting");
    [self upDateCountersResting];

}else if ((!cEventStatus) && (ddayDif > 0)){
    NSLog(@"currentlyRestingAddDays");
    [self currentlyRestingAddDays:&ddayDif];   
}else{
    NSLog(@"final else");
}

I originally didn't have enough () around each statement and only & instead of &&, from the other questions i found i made the changes to come to the above code. But still no success.

In desperation i have added the following code to confirm the variables and am getting the expected results.

if (cEventStatus) {
    NSLog(@"YES status");
}else{
    NSLog(@"NO status");
}

if (ddayDif > 0) {
    NSLog(@"greater than 0");
}else{
   NSLog(@"less than 0");
}

But the if else never gives the expected result, always falls to the final else regardless of variable values.

I am sure this will be a simple issue but any help is appreciated.