Question

I have a c++ program currently working with a vector that uses a character and number as its keys. e.g. myvector['A'][1] = line.substr(0,7). But I need it to work as myvector[1][3] = line.substr(0,7) so I can use both keys as numbers.

In my current working code I had this:

std::vector<std::vector<std::string> >myvector;

I thought simply changing the string to integer would work but I get a “Segmentation Fault (core dumped)” or “cannot convert ‘std::basic_string’ to ‘int’ in assignment” error.

std::vector<std::vector<int> >myvector;

I know that error is very vague but I am new to c++ so I do not how to find any other specific command response for an error. I have looked around on the web for a bunch of examples but have sadly not been able to compile any of them. Any assistance would be greatly appreciated; thank you for your time.

If I am somehow using indexes out of my range here is how I am inputting my indexes.

myvector[rn].resize(100);
std::ifstream fin(argv[3]);
std::string line;
int rn = 0;
int rln = 0;
while( getline(fin, line) ) {  
rn = 0;
while(rn < line.length()/7){
  myvector[rn][rln] = line.substr (rn*7,7);
  rn++;
}
rln++;
}

When I output “line.substr (rn*7,7)” the results are exactly as expected I just cannot set this variable into my vector. Also rn ends up being around 10+ and rln ends at 6.

Answer 1

In C++, string is in double quote "test" not in single code 'test', try:

std::vector<std::vector<std::string> >myvector(3);
myvector[1].resize(10);
myvector[1][3] = "test";
std::cout << myvector[1][3] << std::endl;

Also With std::vector you have no key concept, actually you are calling access operator[].