I want an if-else statement to check whether the a part of the input is a decimal or not? The following program gave an error for input (2.3, 4, 5, 6)

function dd = day_diff(m1, d1, m2, d2)
    m(1:12) = [31 28 31 30 31 30 31 31 30 31 30 31];
    if m1>=13 && m2>=13 && d1>=32 && d2>=32
        dd=-1;
    elseif (m1==2 && d1>=29) || (m2==2 && d2>=29)
        dd=-1;
    elseif (m1==4 && d1>=31) || (m1==6 && d1>=31) || (m1==9 && d1>=31) || (m1==11 && d1>=31)
        dd=-1;
    elseif (m1==1 && d1>=32) || (m1==3 && d1>=32) || (m1==5 && d1>=32) || (m1==7 && d1>=32) || (m1==8 && d1>=32) || (m1==10 && d1>=32) || (m1==12 && d1>=32)
        dd=-1;
    elseif (m2==4 && d2>=31) || (m2==6 && d2>=31) || (m2==9 && d2>=31) || (m2==11 && d2>=31)
        dd=-1;
    elseif (m2==1 && d2>=32) || (m2==3 && d2>=32) || (m2==5 && d2>=32) || (m2==7 && d2>=32) || (m2==8 && d2>=32) || (m2==10 && d2>=32) || (m2==12 && d2>=32)
        dd=-1;
    elseif (m1<=0 || d1<=0) || (m2<=0 || d2<=0)
        dd=-1;
    elseif m1<=12 && m2<=12 && d1<=31 && d2<=31
        dd=abs(sum(m(m1:m2)) - d1 - (m(m2)-d2));
    end
end

Answer 1

[per isakson]

I get a warning (not an error) and that's because 2.3 isn't an integer.

    >> day_diff( 2.3, 4, 5, 6 );
    Warning: Integer operands are required for colon operator when used as index. 
    > In day_diff (line 19)

where line 19 is

    dd=abs(sum(m(m1:m2)) - d1 - (m(m2)-d2));

Add

    inarg = [m1,d1,m2,d2]; 
    if all(inarg==round(inarg))
        disp('all input arguments are whole numbers')
    else
        disp('one or more of the input arguments are NOT whole numbers')
        dd = [];
        return
    end

in the beginning of the function.

[Ashwin Raju]

Thank you for the solution but I want the output as -1 when any input is decimal.

[per isakson]

Thus replace

    dd = [];

by

    dd = -1;

and delete the disp-statements if you don't want the text output in the command window