Program doesn't execute for loop until the end - c++

Question

I'm writing a code to enter subjects' information where I put void function and array as an object. But not sure when I wanna loop it, it doesn't come until the end. Have a look at the code.
void calculateCGPA::getGPA() {
cout << "Enter the the name of the subject: ";
cin >> subjectName;
cout << "Enter the credit hour:";
cin >> credithour;
cout << "Enter the grade: ";
cin >> grade;
}
int main () {
for (year=1; year<=4; year++) {
for (sem=1; sem<=2; sem++) {
cout << "Enter total subject you take in Year " << year << " Semester " << sem <<": ";
cin >> totalSubjectSem;
calculateCGPA ob[totalSubjectSem];
for(int i = 1; i <= totalSubjectSem; i++) {
cout << "Subject " << i << ": \n";
ob[i].getGPA();
}
}
}
return 0;
}
Here's the error. You can see the compiler only shows until entering the subject name but credit hour and grade are omitted. What should I do?
Expected: It should everything in void function until 3 (since I put 3) and then start over again "Enter total subject you take in Year 1 sem 2" but it also omits that

Answer 1

Take note that in C++ 0 is the first element, and n-1 is the last element. By looping to n, you cause a buffer overflow, hence resulting an error.
A solution would be as follows
void calculateCGPA::getGPA() {
cout << "Enter the the name of the subject: ";
cin >> subjectName;
cout << "Enter the credit hour:";
cin >> credithour;
cout << "Enter the grade: ";
cin >> grade;
}
int main () {
for (year=0; year<4; year++) {
for (sem=0; sem<2; sem++) {
cout << "Enter total subject you take in Year " << year << " Semester " << sem <<": ";
cin >> totalSubjectSem;
calculateCGPA ob[totalSubjectSem];
for(int i = 0; i < totalSubjectSem; i++) {
cout << "Subject " << i << ": \n";
ob[i].getGPA();
}
}
}
}

Answer 2

calculateCGPA ob[totalSubjectSem];
It's GCC extension called Variable-length automatic arrays and not valid C++ (because totalSubjectSem is not const). Use std::vector<calculateCGPA> instead.
for(int i = 1; i <= totalSubjectSem; i++) {
Indices start from 0 and going to array_length - 1. On last iteration you reading out of array bounds and program is crashing.