iOS(Object C) 递归方法求和

有等差数列1,2,3,4,5使用递归方法求和:

- (int)sum:(int)value
{
    if (value >5)
    {
        return self.count;
    }
 
    //在外面定义一个全局变量self.count,初始值为0
    self.count = [self sum:value+1] + value;
    
    return self.count;
}

调用验证:

 self.count = 0;
int result = [self sum:1];

不一定使用等差数列求和,无序数组也行

- (void)sum1:(NSMutableArray *)array Index:(int)index
{
    if (index > (int)array.count-1)
    {
        return;
    }
    
    [self sum1:array Index:index+1];
    //在外面定义一个全局变量self.count,初始值为0
    self.count =  self.count + [array[index] intValue];
    
    NSLog(@"self.count==%d",self.count);
}

验证代码:

    self.count = 0;
    NSMutableArray * array = [[NSMutableArray alloc]initWithObjects:@"11",@"6",@"8",@"65",@"33",@"56", nil];
    
    [self sum1:array Index:0];