MATLAB中for循环和while循环，当步进为小数时为什么得到的结果不一致

Question

MATLAB中for循环和while循环，当步进为小数时得到的结果不一致。

%%
clc; close all;
% for循环，整数步进
sum=0;
for n=1:1:2
   sum=sum+1;
end
fprintf('\n[for] step by int, sum=%d, n=%d\n', sum, n);

% while循环，整数步进
sum=0;
n=1;
while n<=2
   sum=sum+1;
   n=n+1;
end
fprintf('\n[while] step by int, sum=%d, n=%d\n', sum, n);

% for循环，小数步进
sum=0;
for n=1:0.1:2
   sum=sum+1;
end
fprintf('\n[for] step by double, sum=%f, n=%f\n', sum, n);

% while循环，小数步进
sum=0;
n=1;
while n<=2
   sum=sum+1;
   n=n+0.1;
end
fprintf('\n[while] step by double, sum=%f, n=%f\n', sum, n);

输出结果：

[for] step by int, sum=2, n=2

[while] step by int, sum=2, n=3

[for] step by double, sum=11.000000, n=2.000000

[while] step by double, sum=10.000000, n=2.000000

Answer 1

要找到问题很简单，你令迭代完成后n-2的取值都显示在命令行，代码如下：

%% 相关参数设置
%%
clc; close all;
% for循环，整数步进
sum=0;
for n=1:1:2
    sum=sum+1;
end
fprintf('\n[for] step by int, sum=%d, n=%d\n', sum, n);

% while循环，整数步进
sum=0;
n=1;
while n<=2
    sum=sum+1;
    n=n+1;
end
fprintf('\n[while] step by int, sum=%d, n=%d\n', sum, n);

% for循环，小数步进
sum=0;
for n=1:0.1:2
    sum=sum+1;
end
fprintf('\n[for] step by double, sum=%f, n=%f\n', sum, n);
n-2
% while循环，小数步进
sum=0;
n=1;
while n<=2
    sum=sum+1;
    n=n+0.1;
end
n-2
fprintf('\n[while] step by double, sum=%f, n=%f\n', sum, n);

运行结果：

[for] step by int, sum=2, n=2

[while] step by int, sum=2, n=3

[for] step by double, sum=11.000000, n=2.000000

ans =

     0


ans =

   8.8818e-16


[while] step by double, sum=10.000000, n=2.000000

结果显示while循环出现了数值精度问题(matlab中最小能识别的数为eps=2.2204e-16)，也就是每次小数计算时会有误差，误差可能多了也可能少了2.2204e-16，多次累计下来就导致最终结果超过了2。
有用希望可以采纳一下哈！