function RETURN=rswap(matrix,a,b)

global noprint
global err

if(exist('matrix')==0) %check if passed matrix is defined
 noprint=1;
sprintf('%s\n','The matrix you have passed as an argument to ROWOP has not been defined.')
error(' ')
end


global undo;
undo=matrix;
mistake=0;

sizecheck=size(matrix);
if (a>sizecheck(1,1))
sprintf('%s\n%s','The first row index you entered exceeds the number of','rows in the given matrix') 
mistake=1;
err=1;
end

if (b>sizecheck(1,1))
sprintf('%s\n%s','The second row index you entered exceeds the number of','rows in the given matrix') 
mistake=1;
err=1;
end

if(mistake>0)
error('  ')
end

tempa=matrix(a,:);
tempb=matrix(b,:);

matrix(a,:)=tempb;
matrix(b,:)=tempa;

RETURN=matrix;




