Can't the double pointer be used like a dictionary?

Question

i'm trying to make apt of subject

char test;
char* testPtr = &test;
char** testPPtr;
testPptr = new char* [100];


for (int i = 0; i < 5; i++) {
    cin >> testPtr;
    testPPtr[i] = testPtr; // math, eng, history, kor, science
}
for (int j = 0; j < 5; j++) {
    cout << testPPtr[j] << endl;
}

i think

testPPtr[0] is assigned to math

testPPtr[1] is assigned to eng

testPPtr[2] is assigned to history

However, all double-pointers are assigned the last stored value(science).

Why is this happening?

I tried this code, but I failed.

char test;
char* testPtr = &test;
char** testPPtr;
testPptr = new char* [100];


for (int i = 0; i < 5; i++) {
    cin >> testPtr;
    testPPtr[i] = new char[100];
    testPPtr[i] = testPtr;
}
for (int j = 0; j < 5; j++) {
    cout << testPPtr[j] << endl;
}

I'd appreciate any help :)

Answer 1

cin >> testPtr; has undefined behaviour. It tries to write characters after test.

Even if you fix that, e.g. by declaring std::string test;, there is only one string in your program, so all the pointers point to the same place.

std::vector<std::string> subjects(5); // Creates 5 empty strings

for (std::string & subject : subjects)
{
    std::cin >> subject; // Read each subject in
}

for (const std::string & subject : subjects)
{
    std::cout << subject; // Write each subject out
}