Print character stored in an array when an event occured

Print character stored in an array when an event occured

I need assistance on how to create the correct logic, to print each
character stored in an array when a button is pushed.
const string teststring[] = {
"a",
"b",
"c",
"d",
};
//when (Circle) button is true
if (_ps3report->PressureCircle = 1 ) {
// print each character from a to z when (circle) is true
for (int i; <=3; i++) {
printf("output: %s\r\n", teststring[i]);
}
}