Default statement works when i remove getchar part.
//First version
int c;
while ((c = getchar()) != EOF){
switch(c){
case 'a': case 'A': printf("aaa"); break;
default: printf("invalid");
}
}
//Second version
int c;
while ((c = getchar()) != EOF){
switch(c){
case 'a': case 'A': printf("aaa"); break;
default: printf("invalid");
}
c = getchar();
}
At the first version default part works together with (case a) when i entered a however at the second version it's not the case. Why is that ?
When you're getting an input with getchar() repeatedly, you need to clear the input buffer in order to scan another input.
In the first version you posted, case:'a' is executed normally, and when the program reaches the end of the while loop, it needs to clear the input buffer. So it performs a scan operation itself (by scanning an empty input) and enters the loop once more.
You can easily clean the buffer at the end of the while loop:
int c;
while ((c = getchar()) != EOF){
switch(c){
case 'a': case 'A': printf("aaa"); break;
default: printf("invalid");
}
getchar(); // Clear input buffer in order to scan next input.
}