Can't find the bug/probleem in my program [duplicate] - c++

Question

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Why is this only returning "yes"
(2 answers)
Closed 6 years ago.
I'm making my first project c++. It's a simple temperature converter.
I made a test section [code 1] with if statements. the if statement would compare the user input. for example if you user typed c and then k(Celsius-Kelvin). it should run the function[code 2] CtoK(); but i doesn't it runs all function why does it do this?
It try to use return but i didn't(it also didn't gave a error so i kept it)
If you guys see something else pls say it Code on pastebin
Also thinks to keep it mind:
Just stated to learn C++
Not native English so if there are spelling and grammar mistakes please say it so i can learn form it
[code 1]
void whatToWhat(char firstDegrees, char secondDegrees) {
if (firstDegrees == 'C' || 'c') {// tests if the user want form c to f
if (secondDegrees == 'F' || 'f') {
CtoF();
}
}if (firstDegrees == 'C' || 'c') {// tests if the user want form c to k
if (secondDegrees == 'K' || 'k') {
CtoK();
}
}if (firstDegrees == 'F' || 'f') {// tests if the user want form f to c
if (secondDegrees == 'C' || 'c') {
FtoC();
}
}if (firstDegrees == 'F' || 'f') {// tests if the user want form f to k
if (secondDegrees == 'K' || 'k') {
FtoK();
}
}if (firstDegrees == 'K' || 'k') {// tests if the user want form k to f
if (secondDegrees == 'F' || 'f') {
KtoF();
}
}if (firstDegrees == 'K' || 'k') {// tests if the user want form k to c
if (secondDegrees == 'C' || 'c') {
KtoC();
}
}
}
[code 2]
void CtoF() {// c to f furmula
double input;
cout << "Enter a number[Celsius-Fahrenheit]" << endl;
cin >> input;
cout << "it's " << input * 1.8 + 32 << " Fahrenheit " << endl;
return;
}
void CtoK() {// c to k furmula
double input;
cout << "Enter a number[Celsius-Kelvin]" << endl;
cin >> input;
cout << "it's " << input + 273.15 << " Kelvin " << endl;
return;
}
void FtoC() {//f to c furmula
double input;
cout << "Enter a number[Fahrenheit-Celsius]" << endl;
cin >> input;
cout << "it's " << input / 1.8 - 32 << " Celsius " << endl;
}
void FtoK() {//f to k furmula
double input;
cout << "Enter a number[Fahrenheit-Kelvin]" << endl;
cin >> input;
cout << "it's " << input / 1.8 - 32 + 273.15 << " Kelvin " << endl;
return;
}
void KtoF() {// k to f furmula
double input;
cout << "Enter a number[Kelvin-Fahrenheit]" << endl;
cin >> input;
cout << "it's " << (input - 273.15) * 1.8 + 32 << " Fahrenheit " << endl;
}
void KtoC() {// k to c furmula
double input;
cout << "Enter a number[Kelvin-Celsius]" << endl;
cin >> input;
cout << "it's " <<273.15 - input << " Celsius " << endl;
return;
}

Answer 1

if(firstDegrees == 'K' || 'k') will always evaluate to true since k as it is is Not Null, means Valid, means True.
You need to write all your expressions in a similar way to this: (firstDegrees == 'K' || firstDegrees == 'k')
Also, you would want to add elses after each if, for better and clearer logic control.