is not prime number command , function to find the nearest prime number

This is the code I have written :

function[k]=next_prime(n)

 k=n
 while ( k~=isprime(k))
     k=k+1
 if k~isprime(k)
     

end
end

I have tried to see what my error is by writing a similar function for the next nearest integer that divides by 5, and another function for the next nearest integer.

function[k]=mod5(n)
k=n
 while ( mod(k,5)~=0)
     k=k+1
end
end

The first function works as expected.

function[k]=nextint(n)
k=n 
 while ( k~=isinteger(k))
     k=k+0.1
end
end

The second one, I seem to be having a similar issue as for the prime function ... it just keeps going adding 1 (0.1 respectively).

(I note that if i set k=1 and write the comman ' k~=isprime(k) ' it returns logical true , 1, whereas we would expect logical false? )

Many thanks for your help.

Answer 1

[Matt J]

function k=next_prime(n)

  k=n
  while ~isprime(k)
     k=k+1
  end
  
end

Answer 2

[Prahelika Gayatri N]

function[k]=next_prime(n)

j=0;

while n>0

if j>n && isprime(j)

k=j;

return

end

j=j+1;

end

[Rik]

What does this answer add to that of Matt? Also, why didn't you format your code?