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Author Topic: Chapter 3 - Exercises (1 until 7)  (Read 2615 times)
gstomi
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« on: August 18, 2013, 07:58:09 AM »

Hey!

Answers for Chapter 3 Exercises:
1)The invalid names are:
6_05 - Variable Numbers can't start with numbers!
A$ - "$" is a invalid character.
Warning:
_calloc is ok, but remember: calloc is a reserved word!
Int starts with "I", uppercase letter, so, it's not a reserved word.
2)
@interface Mac : NSObject

//Really Long Code

@end

@implementation Mac
{
//A billion variables
}
//Really Long Code times 3
@end
int main()
{
Mac * myMacBook = [[myMacBook alloc] init];
[myMacBook turnOn];
myMacBook connectToInternet];
[myMacBook turnOff];
[myMacBook printBatteryLevel];
[myMacBook publishToFacebook: @"Really Long Day..];
}


3) Haha, already did it Tongue

4)
Boat:
[myBoat startEngine];
[myBoat getDiesel:100]; //Add 100 gallons of sea diesel
[myBoat turNightLightsOn];
[myBoat checkRadar: 1000]; //Check 1000 miles area with a radar
[myBoat setSpeed: 40] //Set speed to 40 miles per hour
[myBoat stopEngine];
Motocycle:
[myMotocycle service];
[myMotocycle getGas:30]; //Add 30 gallons of Gas.
[myMotocycle startEngine];
[myMotocycle turnNightLightsOn];
[myMotocycle setSpeed: 20] /*Set speed to 20MPH*/
[myMotocycle stopEngine];

5) Yes, because you don't need to write the same(or atleast really similar) code three or more times.

6)I see advantages on object-oriented programming, because it's simply creating a new instance.

7)
//Cartesian Plans by Gabriel Tomitsuka. No Rights Reserved. You are allowed to modify, republish and
//do whatever you want. Made for Chapter 3 Exercise 7, page 50 of the book "Programming in Objective-C
//4th Edition by Stephan G. Kochan

@interface XYPoint : NSObject

-(void) printCoordinates;
-(void) setX : (int) xcoord;
-(void) setY : (int) ycoord;

@end

@implementation XYPoint
{
    int x;
    int y;
}

-(void) printCoordinates
{
    printf("X: %i \nY: %i", x, y);
}

-(void) setX : (int) xcoord
{
    x = xcoord;
}
-(void) setY : (int) ycoord
{
    y = ycoord;

}
@end

int main()
{
    @autoreleasepool {

        NSLog(@"\n\n              ---\n\nWelcome to Universe Positioning System (UPS)\n \n Your coordinates are: \n\n");
        XYPoint * Instance1 = [[XYPoint alloc] init];
        [Instance1 setX: 123];
        [Instance1 setY: 345];
        [Instance1 printCoordinates];

    }
    
    
}
« Last Edit: August 18, 2013, 01:21:36 PM by gstomi » Logged
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