I tried to write a program but I get segmentation fault (core dumped) while running . When I put a defined array like array_2d[10][1] , the problem is solved but I need to do the memory allocation for my project. It is a simple version of my code:
#include <iostream> #include <cmath> #include <fstream> #include <cstdlib> #include <string> using namespace std; class Exam { private: double** array_2d; unsigned int num; unsigned int num1; public: Exam(); void memoryallocation(); void show(); }; Exam::Exam() { num=10; num1=1; } void Exam::memoryallocation () { double** array_2d = new double*[num]; for (unsigned int i = 0; i < num ;i++) { array_2d[i] = new double[num1]; } } void Exam::show () { ifstream file; file.open("fish.txt"); for (unsigned int i = 0; i < num; i++) { for (unsigned int j = 0; j < num1; j++) { file >> array_2d[i][j]; cout<<array_2d[i][j]<<" "; } cout<<endl; } file.close(); } int main() { Exam E; E.memoryallocation(); E.show(); return 0; } 
