Lecture Slides on Pointers | C Programming for Engineers | CSE A205, Study notes of Engineering

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CSE294A

Introduction to C Programming for Engineers

Lecture

Jeffrey Miller, Ph.D.

Pointers

Pointers enable programs to simulate call-by-reference and to create and manipulate dynamicdata structures (which are data structures that cangrow and shrink at run time)

Pointers are variables whose values are memoryaddresses

All of the scalar variables we have discussedcontain specific values, not memory addresses

Pointer Values

What is the output of each of the printf statements below?

int *count_ptr; int count = 10; count_ptr = &count; printf (“%d”, count); printf (“%d”, *count_ptr); printf (“%d”, count_ptr); printf (“%d”, &count); printf (“%d”, &count_ptr);

Pass by Reference

Using pointers, we can now pass variables by reference

void change_value (int *my_ptr)

*my_ptr

} void change_value (int val)

val

} void main()

int value

int *value_ptr; value_ptr

&value; printf (“%d”, value);

what is printed? change_value(value); printf (“%d”, value);

what is printed? change_value(value_ptr); printf (“%d”, value);

what is printed? change_value(&value); printf (“%d”, value);

what is printed? }

Homework

Homework #6 is posted!