Segmentation fault with wiringPi - c++

Question

I'm fairly new to coding, and I've been trying to write something to write a placeholder to a text document whenever a button attached to a GPIO pin on my RasPi is pressed:
//Write date function//
void record() {
ofstream myFile;
myFile.open("report.txt");
myFile << "Input at SPAM \n";
myFile.close();
}
//myRead function//
void myRead(int i){
if((digitalRead(4) == HIGH) && (i<5)) {
record();
digitalWrite(14, HIGH);
delay(500);
digitalWrite(14, LOW);
++i;
delay(500);
myRead(i);
}
else{
if((digitalRead(4) != HIGH) && (i<5)){
myRead(i);
}
}
}
int main() {
wiringPiSetup();
pinMode(12, OUTPUT);
pinMode(14, OUTPUT);
pinMode(4, INPUT);
digitalWrite(12, HIGH);
digitalWrite(14, LOW);
myRead(1);
digitalWrite(14, HIGH);
delay(5000);
digitalWrite(14, LOW);
return 0;
}
The code compiles without any complaints, but if I run it in terminal without a sudo command, I get a "segmentation fault" error.
When I run it with a sudo command, the program starts and then ends almost immediately.
For reference:
Pin 12 is providing power to a potential divider on the breadboard.
Pin 4 should take the input from this divider.
Pin 14 causes an LED to light whenever there is an input on pin 4.
Whenever I run the program and VERY QUICKLY press the button on the potential divider, the LED will light if I hold the button.
How can I get this to run properly without it stopping as soon as it starts?

Answer 1

I think there are several possible problems with myRead.
A minor rewrite could be:
void myRead(int i)
{
if((digitalRead(4) == HIGH) && (i<5)) {
record();
digitalWrite(14, HIGH);
delay(500);
digitalWrite(14, LOW);
++i;
delay(500);
myRead(i);
} else if((digitalRead(4) != HIGH) && (i<5)) {
myRead(i);
}
}
Notice that you have two calls to digitalRead -- this may lead to problems since the first one my return something different from HIGH and the second may return HIGH, meaning neither conditions are true.
You make a call to myRead with the same i in the alternative branch as the original call. If digitalRead returns something different from HIGH suffeciently many times, your stack will be full very fast and you'll get a segfault.
I'll propose a different version, that should be identical (baring any misunderstanding on my part):
void myRead(int i)
{
// as long as i is less than 5
while (i < 5) {
// busy wait for digitalRead(4) to be HIGH
while (digitalRead(4) != HIGH);
// do the main thing
record();
digitalWrite(14, HIGH);
delay(500);
digitalWrite(14, LOW);
++i;
delay(500);
}
}
Also please note that this is just plain C, not C++ (well, technically it's valid C++, but it's making no use of C++)