OBJECTIVE-C Foundation Framework Practice--nsarray (i) __nsarray

Nsarray is an immutable group in the Foundation framework, let's implement these methods:

#import <Foundation/Foundation.h> int main (int argc, const char * argv[]) {@autoreleasepool {//oc array can be Storing objects of different types; the array of OC can only store objects;//But memory space is still contiguous; Nsarray *arr1 = [[Nsarray alloc] initwithobjects:@ "1", @ "2", @ "3", nil];/
    
    /array finally must end with nil, indicating the end of the array; NSLog (@ "%@", arr1);
    Computes the array length; int count = (int) arr1.count;
    
    NSLog (@ "Count =%d", count);
    Detects whether there is a value in the array; BOOL iscontainer = [arr1 containsobject:@ "5"];
    if (Iscontainer) {NSLog (@ "exists this object");
    }else{NSLog (@ "There is no such object");
    //Get the last object; NSString *lastobj = [arr1 lastobject];
    
    NSLog (@ "lastobj =%@", lastobj);
    Get the first object; NSString *firstobj = [arr1 firstobject];
    
    NSLog (@ "firstobj =%@", firstobj);
    Gets the object at the specified position; nsstring *indexobj = [arr1 objectatindex:2];
    
    NSLog (@ "indexobj =%@", indexobj);
    Gets the location of a specified object;//If the element does not exist, print-1; int index = (int) [arr1 indexofobject:@ "2"];
    
  NSLog (@ "index =%d", index); } RETurn 0; }

The output results are as follows:

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