NSMutableArray基础-创建、添加、删除、替换

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //创建并设定数组元素个数
        NSMutableArray *arr1=[NSMutableArray arrayWithCapacity:7];
        //复制数组
        NSArray *arr2=@[@"mon",@"tue",@"wed",@"thu",@"fri",@"sat",@"sun"];
        NSMutableArray *arr3=[NSMutableArray arrayWithArray:arr2];
        //向数组中添加一个元素
        [arr3 addObject:@"eig"];
        //根据指定下标插入元素
        [arr3 insertObject:@"nin" atIndex:8];
        //删除最后一个元素
        [arr3 removeLastObject];
        //根据指定下标删除元素
        [arr3 removeObjectAtIndex:7];
        //根据指定对象删除元素（若未找到返回NSNotfind
        [arr3 removeObject:@"sun"];
        //替换指定下标的元素
        [arr3 replaceObjectAtIndex:0 withObject:@"one"];
        //删除全部元素
        [arr3 removeAllObjects];
    }
    return 0;
}