# How to solve this without goto statement?

2 次查看（过去 30 天）
Amit Kumar 2014-5-16

Hi all, I think it is bad that matlab doesn't have a goto statement (many people will strongly disagree, but excuse me for the same). I am not a great programmer and I do not know what alternative should be used in the following script:
m1=2140.67;
m2=0.2*m1;
F=440;
k1=0.7*1e6;
w1=sqrt(k1/m1);
c1=10; c2=0; c3=0;
for(k2=1e3:1:1e5)
for (w=18:1e-4:18.1)
x1 = 1/(((-m1*w^2+k1+k2)*(-m2*w^2+k2) - k2^2))*k2*F*1;
% if(abs(x1)>0.0025)
% { goto abc}
if(abs(x1)<c1 && abs(x1)<(0.0025))
c1=x1;
c3=k2;
else
end
end
%abc:
%continue;
end
fprintf('val : x1 = %4.6f m and k2 = %4.6f N/m \n',c1,c3);
There are 2 for loops in this script. I wish that for any value of w, if (abs(x1)>0.0025), the next iteration should begin in outer loop (not the loop of w, so 'continue' is not useful). So what should I do to get next iteration of outer loop i.e. next iteration of k? Had matlab been using goto, I could have employed what is given in % (comments).

### 采纳的回答

Image Analyst 2014-5-16

I don't see a loop over k, just k2. But when that condition happens, put a break in the inner loop
if (abs(x1)>0.0025)
break;
end
and then outside the inner loop but inside the outer k2 loop, put this:
if (abs(x1)>0.0025)
continue;
end
x1 will still have the same value so that should work.
##### 2 个评论显示 无隐藏 无
Image Analyst 2014-5-16
Haven't heard from you so perhaps you need it spelled out exactly. See below:
clc;
workspace;
m1=2140.67;
m2=0.2*m1;
F=440;
k1=0.7*1e6;
w1=sqrt(k1/m1);
c1=10;
c2=0;
c3=0;
tic;
for k2 = 1e3 : 1e5
for w = 18 : 1e-4 : 18.1
x1 = 1/(((-m1*w^2+k1+k2)*(-m2*w^2+k2) - k2^2))*k2*F*1;
if abs(x1) > 0.0025
break;
end
if (abs(x1) < c1 && abs(x1) < (0.0025))
c1=x1;
c3=k2;
end
end
if abs(x1) > 0.0025
continue;
end
end
toc
fprintf('val : x1 = %4.6f m and k2 = %4.6f N/m \n',c1,c3);
I cleaned up a few other things too.
Amit Kumar 2014-5-16
Thanks a lot!

### 更多回答（2 个）

the cyclist 2014-5-16
I am not 100% I understand the logic you are trying to implement, but I think you want the break command.
##### 0 个评论显示 -2更早的评论隐藏 -2更早的评论

Brian B 2014-5-16
for(k2=1e3:1:1e5)
for (w=18:1e-4:18.1)
x1 = 1/(((-m1*w^2+k1+k2)*(-m2*w^2+k2) - k2^2))*k2*F*1;
if(abs(x1)>0.0025)
break;
elseif(abs(x1)<c1 && abs(x1)<(0.0025))
c1=x1;
c3=k2;
end
end
end

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