w5 - CSC209 Dynamic Memory in C Kante Easley University of...

Info icon This preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
CSC209: Dynamic Memory in C Kante Easley University of Toronto June 10, 2009 Kante Easley CSC209
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CSC209: Multidimensional arrays Recall from last lecture: Multidimensional arrays are just single-dimensional arrays stored back to back. int a[2][3] = {{1, 2, 3},{4, 5, 6}}; 1 2 3 4 5 6 C stores multidimensional arrays in row-major order. x[i][j] == *((int*)x + i*n + j) , where n is the row size of x note the cast to int* that wasn’t there last week! Kante Easley CSC209
Image of page 2
CSC209: Dynamic Memory So we know how to create blocks of memory, but we need to know the size of the block before compile time. This is called static memory allocation. We want to do some dynamic memory allocation . Use the commands malloc , calloc . int *a; //nough memory for 1 pointer a = (int*)malloc(6*sizeof(int));//enough memory for 6 int Kante Easley CSC209
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CSC209: Malloc int *a; a = (int*)malloc(6*sizeof(int)); Things to note: The return value of malloc is void* so we should cast it to int* We need to use sizeof to find the number of bytes in an int There is a special return value ( NULL ) for when things go wrong Check out the man page for malloc Kante Easley CSC209
Image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern