Centigrade to Fahrenheit Converter doesn't work properly

I want to create a function to convert degrees Celsius to degrees Fahrenheit and return the result as the function output. When I input a number to convert the answer is the same number instead of the converted amount. For example, when I put 40 the answer is 40. It should be 104. How can I fix this?

function F = C2F(C)

C = input('Input the temperature in Celsius that you want to convert to Farenheit:');

F = 1.8*C + 32;

end

Answer 1

[VBBV]

C = 40; %input('Input the temperature in Celsius that you want to convert to Farenheit:');
C2F(C)

ans = 104

function F = C2F(C)

F = 1.8*C + 32;
end

[VBBV]

C = input('Input the temperature in Celsius that you want to convert to Farenheit:');

Put this line outside of the function and invoke this statement at command window.

Alternately you can remove the input arguments to the function C2F and call as shown below

C2F
function F = C2F()
C = input('Input the temperature in Celsius that you want to convert to Farenheit:');
F = 1.8*C + 32;
end

[Laura]

I have changed the script to:

C2F()

function F = C2F()

C = input('Input the temperature in Celsius that you want to convert to Farenheit:');

F = 1.8*C + 32;

end

It converts the 40 to 104 but how can I get it to convert a negative number?

[Walter Roberson]

-40 C is famously -40 F .

-40 C is not -104 F . The conversion is not symmetric around 0.

Answer 2

[Sam Chak]

Hey @Laura, there doesn't seem to be any issue with the code when the input() command is placed outside of the C2F() function.

% C = input('Input the temperature in Celsius that you want to convert to Farenheit:');
C   = 40;
F   = C2F(C)

F = 104

function F = C2F(C)
    F = 1.8*C + 32;
end

[Laura]

I would like to put in any amount to be converted, not only 40.

[Stephen23]

"I would like to put in any amount to be converted, not only 40."

You can use any input value you want, not only 40. Just like every other MATLAB function, when you define your own functions you can call them with any input values you want. In fact, that is rather the whole point of writing functions.

How exactly would MATLAB would stop you from calling your function with a value of 23.5 or -16 or 999?

This is the best approach. One day you will just have to unlearn using INPUT everywhere.