Using nested loops, write a Matlab program that goes through all elements of a matrix (2D array) and replaces every element that is either a multiple of 5 or 7 with -1.

This is what I have so far...

A=input('enter an array');

num_rows = size(A,1);

num_cols = size(A,2);

for i=1:1:num_rows

for j=1:1:num_cols

if A(i,j)/ 5 or 7 = integer

fprintf('-1')

end

end

end

I'm not sure how to identify the multiples of 5 and 7 and make them replace that with the -1

Answer 1

[Roger Stafford]

Your test on a number x from your array can be:

if round(x/5)==x/5 | round(x/7)==x/7

(Doing fprintf('-1') just prints out "-1" and is totally useless for your purposes.)

[Ciara Gornoski]

I did this and I'm still not getting anything.

A=input('enter an array');

num_rows = size(A,1);

num_cols = size(A,2);

for i=1:1:num_rows

for j=1:1:num_cols

if round(A(i,j)/5)==A(i,j)/5 || round(A(i,j)/7)==A(i,j)/7

   end

end

end

I'm just able to input an array but it doesn't give me an output.

[Walter Roberson]

if ...
  A(i,j) = -1;