遍历数组、数组排序

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{
    //数组中建议存储同类型的数据元素
    
    NSArray * array = @[@"one",@"two",@"three"];
    for (int i = 0; i < array.count; i++) {
        NSString * str = array[i];
        NSLog(@"array[%d] = %@",i,str);
    }
    //使用增强for循环遍历数组
    for (NSString * str in array) {
        NSLog(@"%@",str);
    }
    

    return 0;
}

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{

    
        NSArray * array = @[@"1",@"2",@"3",@"4"];
        NSLog(@"before sort%@",array);
        
        //排序
        NSComparisonResult  cmp = [@"a" compare:@"b"];
        //
        NSLog(@"%d",cmp);
        array = [array sortedArrayUsingSelector:@selector(compare:)];
        //正序 左边小于右边
        
        NSLog(@"after sort %@",array);
        
        //(void)(^block)(int a ,int b);
        NSArray * arry1 = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1,id obj2)
        {
            return [obj1 compare:obj2];
        }];
}