Example

void main( int argc, char* argv[]) {
for ( int i = 0; i < argc; i++ ) {
if ( ! isalpha(argv[0]) ) {
cout << "Not a letter";
} else {
cout << "A letter";
}
}
}
Solution
  1. Remove the negation
  2. Switch if and else parts

void main( int argc, char* argv[]) {
for ( int i = 0; i < argc; i++ ) {
if ( isalpha(argv[0]) ) {
cout << "A letter";
} else {
cout << "Not a letter";
}
}
}