Presentation is loading. Please wait.

Presentation is loading. Please wait.

Pointer, malloc and realloc 1. Name entered was 6 char, not enough space to put null terminator 2 Array of char.

Published byAmbrose Lester Thompson Modified over 9 years ago

Similar presentations

Presentation on theme: "Pointer, malloc and realloc 1. Name entered was 6 char, not enough space to put null terminator 2 Array of char."— Presentation transcript:

1 pointer, malloc and realloc 1

2 Name entered was 6 char, not enough space to put null terminator 2 Array of char

3 3 Pointer to array of char

4 3.cpp(15) : error C2440: '=' : cannot convert from 'int' to 'int *' 4 Pointer to array name[] vs Pointer to variable age (wrong version)

5 4.cpp(14) : warning C4313: 'printf' : '%d' in format string conflicts with argument 1 of type 'int *' 5 Pointer to array name[] vs Pointer to variable age (correct version)

6 6 Access address and value pointed by pointer to array name[] Access address and value pointed by pointer to variable age

7 7 strlen()

8 8 nameptr points to an empty offset (with size 5 bytes) allocate new memory using malloc, determine no of offset by strlen name azlan [0][1][2][3][4] nameptr

9 9 char *strcpy(char *destination, const char *source); The argument order mimics that of an assignment: destination "=" source. The return value is destination strcpy() – copy value from array to offset name azlan [0][1][2][3][4] nameptr azlan

10 10 Null terminator nameptr azlan [0][1][2][3][4] \0 [5] Use for loop to go to each offset

11 11 azlan [0][1][2][3][4] nameptr Go to the next offset nameptr++ azlan [0][1][2][3][4] [0][1][2][3] nameptr++ will makes nameptr point to the next offset

12 12 azlan [0][1][2][3][4] name azlan [0][1][2][3][4] nameptr 12ff58 12ff4c 363150363151363152363153363154 12ff5912ff5a12ff5b12ff5c &name = &name[0] = 12ff58 Line 16, create 1 byte x 5 offset Line 17, copy string from name to nameptr Check the address for each array name[] element and nameptr offset

13 13 azlan [0][1][2][3][4] name 12ff5812ff5912ff5a12ff5b12ff5c &name = &name[0] = 12ff58 azlan [0][1][2][3][4] tempptr 12ff4c 363150363151363152363153363154 363150 [0] listptr 12ff40 363188 **listptr – pointer to pointer

14 14 [0] ptr 12ff60 364d68 [0] 363180 [0] 363150 364d68 [0] 3631b0 363180 [1] 3631b4 363150 [2] 3631b8 listptr 12ff54 realloc() – continue create a new offset, to point to other address

15 15 363150 3631e8 3631b0 3631ec 363220 3631f0 listptr 12ff14 a [0] ptr 363150 l [1] 363151 i [2] 363152 c [0] 3631b0 h [1] 3631b1 o [2] 3631b2 n [3] 3631b3 g [4] 3631b4 m [0] 363220 u [1] 363221 t [2] 363222 h [3] 363223 u [4] 363224 [0][1][2] when offset=0 when offset=1 when offset=2 Line 11-create new malloc, line 12-copy value from name[] to ptr, line 18-create new offset, line 15 and 19-offset points to where ptr points

Download ppt "Pointer, malloc and realloc 1. Name entered was 6 char, not enough space to put null terminator 2 Array of char."

Similar presentations

Introduction to C Programming

Introduction to C Programming
Incomplete Structs struct B; struct A { struct B * partner; // other declarations… }; struct B { struct A * partner; // other declarations… };

Incomplete Structs struct B; struct A { struct B * partner; // other declarations… }; struct B { struct A * partner; // other declarations… };
C’ POINTERS Basic&Examples. Q:what’s the output? int array[] = { 45, 67, 89 }; int *array_ptr = array; printf( first element: %i\n, *(array_ptr++));

C’ POINTERS Basic&Examples. Q:what’s the output? int array[] = { 45, 67, 89 }; int *array_ptr = array; printf(" first element: %i\n", *(array_ptr++));
Dynamic memory allocation

Dynamic memory allocation
 A string is an array of characters.  Strings must have a 0 or null character after the last character to show where the string ends.  The null character.

 A string is an array of characters.  Strings must have a 0 or null character after the last character to show where the string ends.  The null character.
Dynamic Memory Allocation in C.  What is Memory What is Memory  Memory Allocation in C Memory Allocation in C  Difference b\w static memory allocation.

Dynamic Memory Allocation in C.  What is Memory What is Memory  Memory Allocation in C Memory Allocation in C  Difference b\w static memory allocation.
Constructor. 2 constructor The main use of constructors is to initialize objects. A constructor is a special member function, whose name is same as class.

Constructor. 2 constructor The main use of constructors is to initialize objects. A constructor is a special member function, whose name is same as class.
Chapter 6 Data Types. 2 3 4 5 6 7 8 9 10.

Chapter 6 Data Types
C Characters & Strings Character Review Character Handling Library Initialization String Conversion Functions String Handling Library Standard Input/Output.

C Characters & Strings Character Review Character Handling Library Initialization String Conversion Functions String Handling Library Standard Input/Output.
 2003 Prentice Hall, Inc. All rights reserved. 5.12.1 Fundamentals of Characters and Strings Character constant –Integer value represented as character.

 2003 Prentice Hall, Inc. All rights reserved Fundamentals of Characters and Strings Character constant –Integer value represented as character.
Strings.

Strings.
1 Chapter 10 Strings and Pointers. 2 Introduction  String Constant  Example: printf(“Hello”); “Hello” : a string constant oA string constant is a series.

1 Chapter 10 Strings and Pointers. 2 Introduction  String Constant  Example: printf(“Hello”); “Hello” : a string constant oA string constant is a series.
Character String Manipulation. Overview Character string functions sscanf() function sprintf() function.

Character String Manipulation. Overview Character string functions sscanf() function sprintf() function.
Character String Manipulation. Overview Character string functions sscanf() function snprintf() function.

Character String Manipulation. Overview Character string functions sscanf() function snprintf() function.
Lecture 20 Arrays and Strings

Lecture 20 Arrays and Strings
What is a pointer? First of all, it is a variable, just like other variables you studied So it has type, storage etc. Difference: it can only store the.

What is a pointer? First of all, it is a variable, just like other variables you studied So it has type, storage etc. Difference: it can only store the.
Strings CS240 Dick Steflik. What is a string A null terminated array of characters: char thisIsAString[10]; 0 1 2 3 4 5 6 7 8 9 \0 The “\0” (null character)

Strings CS240 Dick Steflik. What is a string A null terminated array of characters: char thisIsAString[10]; \0 The “\0” (null character)
Current Assignments Homework 5 will be available tomorrow and is due on Sunday. Arrays and Pointers Project 2 due tonight by midnight. Exam 2 on Monday.

Current Assignments Homework 5 will be available tomorrow and is due on Sunday. Arrays and Pointers Project 2 due tonight by midnight. Exam 2 on Monday.
Chapter Fourteen Strings Revisited. Strings A string is an array of characters A string is a pointer to a sequence of characters A string is a complete.

Chapter Fourteen Strings Revisited. Strings A string is an array of characters A string is a pointer to a sequence of characters A string is a complete.
Array_strcpy void array_strcpy(char dest[], char src[]) { int i = 0; while (src[i] != '\0') { dest[i] = src[i]; i++; } dest[i] = '\0'; }

Array_strcpy void array_strcpy(char dest[], char src[]) { int i = 0; while (src[i] != '\0') { dest[i] = src[i]; i++; } dest[i] = '\0'; }

Similar presentations

Ads by Google