# Writing a function that merges two sorted vectors

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Lee Cohen am 21 Apr. 2018
Kommentiert: Ameer Hamza am 22 Apr. 2018
Hello, I need to write a function that merge two sorted vectors to one sorted vector that containes all the values.
My code is:
vec1= input('enter vec1\n');
vec2= input('enter vec2\n');
vec1=sort(vec1)
vec2=sort(vec2)
function [res]=merge(vec1, vec2)
n1=length(vec1);
n2=length(vec2);
n=n1+n2;
res=zeros(n, 1);
if n1==0
res=vec2;
elseif n2==0
res=vec1; else
i1=1;
i2=1;
end
for j=1:n
if i1>n1
res(j)=vec2(i2);
i2=i2+1;
elseif i2>n2 res(j)=vec(i1); i1=i1+1;
elseif vec(i1)<vec(i2)
res(j)=vec(i1);
i1=i1+1;
else
res(j)=vec2(i2);
i2=i2+1;
end
end
end
My questions are: Is my code right and how can I call the new function that I created? (I saved the file named 'merge' in a function file).
##### 1 KommentarKeine anzeigenKeine ausblenden
Ameer Hamza am 21 Apr. 2018

First of all, you should format your code properly: https://www.mathworks.com/matlabcentral/answers/7885-tutorial-how-to-format-your-question so that others can easily read it.

There are some mistakes in your merge function. You are using vec on some lines instead of vec1 or vec2, so it is difficult for me to understand what do mean by merging two sorted vectors. Still, I have tried to answer this question according to my understanding of this code. You can see it in answer section below.

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### Akzeptierte Antwort

Ameer Hamza am 21 Apr. 2018

If you simply want to join two sorted vectors you can use

```new_vec = [vec1 vec2];
```

but this seems improbable to me since joining two sorted vectors like this may not be very useful. The second possibility is, you also want to sort the result, you can do that as

```new_vec = sort([vec1 vec2]);
```

In this second case, you don't even need to run

```vec1=sort(vec1)
vec2=sort(vec2)
```

because the command I mentioned will sort both of them together.

In either case, no need to write your own merge function. You can use MATLAB builtin function to reach same results.

##### 2 Kommentare1 älteren Kommentar anzeigen1 älteren Kommentar ausblenden
Ameer Hamza am 22 Apr. 2018

Yes, Your function is giving correct output. You can just try by calling the function like this

```merged_vector = merge(vec1, vec2);
```

You can add this line before the definition of the function merge.

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