Method overloading, overwriting, and hiding in objective-C

In C ++, class methods include overload, override, and hide (of course, functions can also be overloaded .).

The coverage and hiding of C ++ is a very confusing concept, especially hidden. Learn objective-C, because it is similar to C ++, so pay special attention to this.

From the followingCodeTest results show that OC is far less flexible than C ++ ". The output of specific conclusions is clear at a glance.

/** <Br/> * test_hide.m <br/> */</P> <p> # import <Foundation/Foundation. h> </P> <p> // ---- @ interface section ---- </P> <p> // base <br/> @ interface base: nsobject <br/>/* {} * // It's optional. <br/> + (void) Foo; <br/> + (void) FOO: (INT) Param; <br/> + (void) FOO: (INT) param and: (INT) param2; <br/> + (void) FOO: (INT) PARAM and: (INT) param2 and: (INT) param3; <br/>-(void) bar; <br/>-(void) bar: (INT) para M; <br/>-(void) bar: (INT) PARAM and: (INT) param2; <br/>-(void) bar: (INT) PARAM and: (INT) param2 and: (INT) param3; <br/> @ end </P> <p> // derived <br/> @ interface derived: base <br/> + (void) FOO: (INT) Param; <br/>-(void) bar: (INT) PARAM and: (INT) param2; <br/> @ end </P> <p> // ---- program section ---- </P> <p> int main (INT argc, char * argv []) <br/> {<br/> NSAID utoreleasepool * Pool = [NSAID utoreleasepool al Loc] init]; </P> <p> [base Foo]; <br/> [base FOO: 1]; <br/> [base FOO: 1 and: 2]; <br/> [base FOO: 1 and: 2 and: 3]; </P> <p> base * base = [[base alloc] init]; <br/> [base bar]; <br/> [base bar: 1]; <br/> [base bar: 1 and: 2]; <br/> [base bar: 1 and: 2 and: 3]; <br/> [base release]; </P> <p> nslog (@ "-------- <1> --------"); </P> <p> [derived Foo]; // OK, either! Not hided. <br/> [derived FOO: 11]; // OK <br/> [derived FOO: 11 and: 22]; // OK, either! Not hided. <br/> [derived FOO: 11 and: 22 and: 33]; // OK, either! Not hided. </P> <p> derived * derived = [[derived alloc] init]; <br/> [derived bar]; // OK, either! Not hided. <br/> [derived bar: 11]; // OK, either! Not hided. <br/> [derived bar: 11 and: 22]; // OK <br/> [derived bar: 11 and: 22 and: 33]; // OK, either! Not hided. <br/> [derived release]; </P> <p> nslog (@ "-------- <2> --------"); </P> <p> [pool drain]; <br/> return 0; <br/>}</P> <p> // ---- @ implementation section ---- </P> <p> // base <br/> @ implementation base /*: nsobject * // It's optional. <br/> + (void) Foo <br/> {<br/> nslog (@ "base: foo "); <br/>}</P> <p> + (void) FOO: (INT) Param <br/>{< br/> nslog (@ "base: FOO: % I ", Param); <br/>}</P> <p> + (void) FOO: (INT) PARAM and: (INT) param2 <br/>{< br/> nslog (@ "base: FOO: % I and: % I", Param, param2 ); <br/>}</P> <p> + (void) FOO: (INT) PARAM and: (INT) param2 and: (INT) param3 <br/>{< br/> nslog (@ "base: FOO: % I and: % I", Param, param2, param3 ); <br/>}</P> <p>-(void) bar <br/>{< br/> nslog (@ "base: bar "); <br/>}</P> <p>-(void) bar: (INT) Param <br/>{< br/> nslog (@ "base: bar: % I ", Param); <br/>}</P> <p>-(void) bar: (INT) PARAM and: (INT) param2 <br/>{< br/> nslog (@ "base: bar: % I and: % I", Param, param2 ); <br/>}</P> <p>-(void) bar: (INT) PARAM and: (INT) param2 and: (INT) param3 <br/>{< br/> nslog (@ "base: bar: % I and: % I", Param, param2, param3 ); <br/>}< br/> @ end </P> <p> // derived <br/> @ implementation derived <br/> + (void) FOO: (INT) Param <br/>{< br/> nslog (@ "derived: FOO: % I", Param ); <br/>}</P> <p>-(void) bar: (INT) PARAM and: (INT) param2 <br/>{< br/> nslog (@ "derived: bar: % I and: % I", Param, param2 ); <br/>}< br/> @ end <br/>

// Output </P> <p> 03:31:20. 642 test_hide [3700] Base: Foo <br/> 03:31:20. 658 test_hide [3700] Base: FOO: 1 <br/> 03:31:20. 658 test_hide [3700] Base: FOO: 1 and: 2 <br/> 03:31:20. 658 test_hide [3700] Base: FOO: 1 and: 2 and: 3 <br/> 03:31:20. 673 test_hide [3700] Base: bar <br/> 03:31:20. 673 test_hide [3700] Base: bar: 1 <br/> 03:31:20. 673 test_hide [3700] Base: bar: 1 and: 2 <br/> 03:31:20. 689 test_hide [3700] Base: bar: 1 and: 2 and: 3 <br/> 03:31:20. 689 test_hide [3700] -------- <1> -------- <br/> 03:31:20. 689 test_hide [3700] Base: Foo <br/> 03:31:20. 705 test_hide [3700] derived: FOO: 11 <br/> 03:31:20. 705 test_hide [3700] Base: FOO: 11 and: 22 <br/> 03:31:20. 705 test_hide [3700] Base: FOO: 11 and: 22 and: 33 <br/> 03:31:20. 720 test_hide [3700] Base: bar <br/> 03:31:20. 720 test_hide [3700] Base: bar: 11 <br/> 03:31:20. 720 test_hide [3700] derived: bar: 11 and: 22 <br/> 03:31:20. 736 test_hide [3700] Base: bar: 11 and: 22 and: 33 <br/> 03:31:20. 736 test_hide [3700] -------- <2> --------