how to create a .txt file of output for a program in Matlab \"sprintf\"?????????

Question

how to create a .txt file of output for a program in Matlab     "sprintf"??????????????????

The out I am getting from my function for finding the roots of a quadratic formula needs to be saved and printed in a .txt file..............

Copy of my formula

function [ root1,root2 ] = quadratic_formula( a,b,c )

% Design a Matlab using the algorithm for solving quadratic equations

% Prompt the user to enter the coefficients

% ax^2+bx+c = 0

a(1) = input('Please enter a value for (a) >> ');

b(1) = input('Please enter a value for (b) >> ');

c(1) = input('Please enter a value for (c) >> ');

if a == 0

disp('Error: Value Will Result In An Undefined Answer')

disp('PLEASE ENTER A VALUE > 0')

end

if b^2-4*a*c > 0

root1 = (-b+sqrt(b^2-4*a*c))/2*a; % Root of the equation

root2 = (-b-sqrt(b^2-4*a*c))/2*a;

elseif b^2-4*a*c == 0;

root1 = -b/2*a;

disp('There is only one root')

else

disp(' Error: Imaginary Roots')

disp('No Real Solution')

end

end

Explanation / Answer

fprintf is used to save a data to .txt file in MATLAB.

first you need to open a file in write mode with a file handler like

myfile = fopen('File.txt', 'w');

where w indicates file with file handler myfile and filename File.txt is in write mode.

now when you want to save the data to File.txt use fprintf as below:

it will save the value of B in File.txt

and than close the file using file handle as below:

fclose(myfile);

now for your MATLAB program find the updated program as below:

function [ root1,root2 ] = quadratic_formula( a,b,c )
% Design a Matlab using the algorithm for solving quadratic equations
% Prompt the user to enter the coefficients
% ax^2+bx+c = 0

% open File.txt with handle myfile in write mode

myfile = fopen('File.txt', 'w');

a(1) = input('Please enter a value for (a) >> ');
b(1) = input('Please enter a value for (b) >> ');
c(1) = input('Please enter a value for (c) >> ');

if a == 0
disp('Error: Value Will Result In An Undefined Answer')
disp('PLEASE ENTER A VALUE > 0')
end

if b^2-4*a*c > 0

root1 = (-b+sqrt(b^2-4*a*c))/2*a; % Root of the equation
root2 = (-b-sqrt(b^2-4*a*c))/2*a;

%save values of root1 and root2 in File.txt

fprintf(myfile,'%0.4f ',root1);
fprintf(myfile,'%.4f ',root2);

elseif b^2-4*a*c == 0;
root1 = -b/2*a;

%save values of root1 in File.txt
fprintf(myfile,'%.4f ',root1);

disp('There is only one root')

else

disp(' Error: Imaginary Roots')
disp('No Real Solution')

end

end

fclose(myfile);

or you can also do like this in which every display statement is also in File.txt

function [ root1,root2 ] = quadratic_formula( a,b,c )
% Design a Matlab using the algorithm for solving quadratic equations
% Prompt the user to enter the coefficients
% ax^2+bx+c = 0

% open File.txt with handle myfile in write mode

myfile = fopen('File.txt', 'w');

pqr1 = 'Error: Value Will Result In An Undefined Answer';
pqr2 = 'PLEASE ENTER A VALUE > 0';
pqr3 = 'There is only one root';
pqr4 = ' Error: Imaginary Roots';
pqr5 = 'No Real Solution';

a(1) = input('Please enter a value for (a) >> ');
b(1) = input('Please enter a value for (b) >> ');
c(1) = input('Please enter a value for (c) >> ');

if a == 0
%save display statement in File.txt
fprintf(myfile,'%s ',pqr1);
fprintf(myfile,'%s ',pqr2);
end

if b^2-4*a*c > 0

root1 = (-b+sqrt(b^2-4*a*c))/2*a; % Root of the equation
root2 = (-b-sqrt(b^2-4*a*c))/2*a;

%save values of root1 and root2 in File.txt

fprintf(myfile,'%0.4f ',root1);
fprintf(myfile,'%0.4f ',root2);

elseif b^2-4*a*c == 0;
root1 = -b/2*a;

%save values of root1 in File.txt
fprintf(myfile,'%0.5fn',root1);

%save display statement in File.txt

fprintf(myfile,'%s ',pqr3);

else

%save display statement in File.txt

fprintf(myfile,'%s ',pqr4);
fprintf(myfile,'%s ',pqr5);

end

end

fclose(myfile);

note %.4f will display result upto 4 decimal places.

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