Arrays on Data Structure and Algorithms related Questions and Answers

Question :   How do you allocate a matrix using a single pointer in C?(r and c are the number of rows and columns respectively) 1. int *arr = malloc(r * c * sizeof(int)); 2. int *arr = (int *)malloc(r * c * sizeof(int)); 3. int *arr = (int *)malloc(r + c * sizeof(int)); 4. int *arr = (int *)malloc(r * c * sizeof(arr)); Answer :   2 - int *arr = (int *)malloc(r * c * sizeof(int));