Adding and deleting from array

Question

i have this peace of code i don't understand :
adding:
public boolean addCourse(String course) {
for (int i = 0; i < numCourses; i++) {//i'm checking whether course is in the list
if (courses[i].equals(course)) return false;
}
courses[numCourses] = course;//if not he is added
numCourses++;
return true;
}
removing:
public boolean removeCourse(String course) {//i don't understand following so if someone could explain line by line, thx
boolean found = false;
int courseIndex = -1;
for (int i = 0; i < numCourses; i++) {
if (courses[i].equals(course)) {
courseIndex = i;
found = true;
break;
}
}
if (found) {

for (int i = courseIndex; i < numCourses-1; i++) {
courses[i] = courses[i+1];
}
numCourses--;
return true;
} else {
return false;
}
}

Answer 1

E.g.

1 2 3 4 5 6 7

We want to delete 4, so the program loops until it finds 4. 4 is at index 3. The program will start to loop from index 3 to index array_size - 1, and shift all arrays to the left, "covering" 4.

1 2 3 4 <- 5 <- 6 <- 7

result : 1 2 3 5 6 7