For and While loop give different answers

% while loop 
X1=1.5;
Y1=5;
Z1=26;
while Y1 < 30
    cot = cotd(Y1);
    while Z1 < 50
        Zt1 = tand(Z1) * (((2.2) * X1^2));
        check = (Zt1-cot)/cot;
        if check <= 10^-2
            break
        end
        Z1 = Z1+10^-5;
    end
    Xn1 = X1*sind(Z1);
    X2 = sqrt((((0.2)* X1^2*sind(Z1)^2) + 2));
    Z2 = asind(Xn1/X2);
    Y2 = acotd(tand(Z2) * (((2.2) * X2^2)));
        
    X3 = sqrt((((0.2)* X2^2*sind(Z2)^2) + 2));
    Z3 = asind(Xn1/X3);
    Y3 = acotd(tand(Z3) * (((2.2) * X3^2)));
     
    X4 = sqrt((((0.2)* X3^2*sind(Z3)^2) + 2));
    X4_2 = 1.6;
    X4_1 = (X4 - X4_2);
    check2 =  X4_1/X4_2;
    if  check2 <= 10^-5
        break
    end
    Y1 = Y1+10^-5;    
end 
--------------------
% for loop
X1=1.5;
for Y1 = (5:0.01:30)
    cot = cotd(Y1); 
    for Z1 = 26:2:45
        Zt1 = tand(Z1) * (((2.2) * X1^2));;
        check = (Zt1-cot)/cot;
        if check <=10^-2
            break
        end
        Xn1 = X1*sind(Z1);
        X2 = sqrt((((0.2)* X1^2*sind(Z1)^2) + 2));
        Z2 = asind(Xn1/X2);
        Y2 = acotd(tand(Z2) * (((2.2) * X2^2)));
            
        X3 = sqrt((((0.2)* X2^2*sind(Z2)^2) + 2));
        Z3 = asind(Xn1/X3);
        Y3 = acotd(tand(Z3) * (((2.2) * X3^2)));
         
        X4 = sqrt((((0.2)* X3^2*sind(Z3)^2) + 2));
        X4_2 = 1.6;
        X4_1 = (X4 - X4_2);
        check2 =  X4_1/X4_2;
        if  check2 <= 10^-5
            break
        end
    end
end

I dont know why this two code end up with different velues of Y1, cot and check.

For While loop, check is -0.7888 but check is 0.3939 at for loop.

I wanna fix for loop and the values are same as while loop

Thank you

[Walter Roberson]

    Y1 = Y1+10^-5;   

for Y1 = (5:0.01:30)

Those are not the same increment.

[HAHA]

even tho I make same increment, answer is different.....

[Stephen23]

Original question from Google Cache:

"For and While loop give different answers"

% while loop 
X1=1.5;
Y1=5;
Z1=26;
while Y1 < 30
    cot = cotd(Y1);
    while Z1 < 50
        Zt1 = tand(Z1) * (((2.2) * X1^2));
        check = (Zt1-cot)/cot;
        if check <= 10^-2
            break
        end
        Z1 = Z1+10^-5;
    end
Xn1 = X1*sind(Z1);
X2 = sqrt((((0.2)* X1^2*sind(Z1)^2) + 2));
Z2 = asind(Xn1/X2);
Y2 = acotd(tand(Z2) * (((2.2) * X2^2)));
    
X3 = sqrt((((0.2)* X2^2*sind(Z2)^2) + 2));
Z3 = asind(Xn1/X3);
Y3 = acotd(tand(Z3) * (((2.2) * X3^2)));
 
X4 = sqrt((((0.2)* X3^2*sind(Z3)^2) + 2));
X4_2 = 1.6;
    X4_1 = (X4 - X4_2);
    check2 =  X4_1/X4_2;
    if  check2 <= 10^-5
        break
    end
    Y1 = Y1+10^-5;    
end 
--------------------
% for loop
X1=1.5;
for Y1 = (5:0.01:30)
     cot = cotd(Y1); 
    for Z1 = 26:2:45
        Zt1 = tand(Z1) * (((2.2) * X1^2));;
     check = (Zt1-cot)/cot;
        if check <=10^-2
            break
        end
Xn1 = X1*sind(Z1);
X2 = sqrt((((0.2)* X1^2*sind(Z1)^2) + 2));
Z2 = asind(Xn1/X2);
Y2 = acotd(tand(Z2) * (((2.2) * X2^2)));
    
X3 = sqrt((((0.2)* X2^2*sind(Z2)^2) + 2));
Z3 = asind(Xn1/X3);
Y3 = acotd(tand(Z3) * (((2.2) * X3^2)));
 
X4 = sqrt((((0.2)* X3^2*sind(Z3)^2) + 2));
X4_2 = 1.6;
    X4_1 = (X4 - X4_2);
    check2 =  X4_1/X4_2;
    if  check2 <= 10^-5
        break
    end
end
end

I dont know why this two code end up with different velues of Y1, cot and check.

For While loop, check is -0.7888 but check is 0.3939 at for loop.

I wanna fix for loop and the values are same as while loop

Thank you

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Geoff Hayes]

I formatted your code so it might be a little more clear what is going on. Here is the while loop code

while Y1 < 30
    cot = cotd(Y1);
    while Z1 < 50
        Zt1 = tand(Z1) * (((2.2) * X1^2));
        check = (Zt1-cot)/cot;
        if check <= 10^-2
            break
        end
        Z1 = Z1+10^-5;
    end
    % the remaining code is in the outer while loop   <-----------------------
    Xn1 = X1*sind(Z1);
    X2 = sqrt((((0.2)* X1^2*sind(Z1)^2) + 2));
    Z2 = asind(Xn1/X2);
    Y2 = acotd(tand(Z2) * (((2.2) * X2^2)));
        
    X3 = sqrt((((0.2)* X2^2*sind(Z2)^2) + 2));
    Z3 = asind(Xn1/X3);
    Y3 = acotd(tand(Z3) * (((2.2) * X3^2)));
     
    X4 = sqrt((((0.2)* X3^2*sind(Z3)^2) + 2));
    X4_2 = 1.6;
    X4_1 = (X4 - X4_2);
    check2 =  X4_1/X4_2;
    if  check2 <= 10^-5
        break
    end
    Y1 = Y1+10^-5;    
end 

Now contrast that with the for loop code

for Y1 = (5:0.01:30)
    cot = cotd(Y1); 
    for Z1 = 26:2:45
        Zt1 = tand(Z1) * (((2.2) * X1^2));;
        check = (Zt1-cot)/cot;
        if check <=10^-2
            break
        end
        % the remaining code is in the inner for loop   <-----------------------
        Xn1 = X1*sind(Z1);
        X2 = sqrt((((0.2)* X1^2*sind(Z1)^2) + 2));
        Z2 = asind(Xn1/X2);
        Y2 = acotd(tand(Z2) * (((2.2) * X2^2)));
            
        X3 = sqrt((((0.2)* X2^2*sind(Z2)^2) + 2));
        Z3 = asind(Xn1/X3);
        Y3 = acotd(tand(Z3) * (((2.2) * X3^2)));
         
        X4 = sqrt((((0.2)* X3^2*sind(Z3)^2) + 2));
        X4_2 = 1.6;
        X4_1 = (X4 - X4_2);
        check2 =  X4_1/X4_2;
        if  check2 <= 10^-5
            break
        end
    end

You have a chunk of code that is evaluated in the outer while loop and that same code appears to be evaluated in the inner for loop. Please confirm which inner or outer loop should be evaluating this code and then make consistent for both.