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Fp201 unit4

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Fp201 unit4

  1. 1. F2037 - PROGRAMMINGFUNDAMENTAL WITH C++Unit 4.1 - Understand the use of array
  2. 2. INDEX Objective Introduction to Array One dimensional array Two dimensional array
  3. 3. OBJECTIVES At the end of this module, students should be able to:  Declare and use an array  Use the array statement in C++ program  Accessing element in an array
  4. 4. ARRAY DEFINITION Array is a collection of data elements of the same type that are referenced by a common name. Used to process a collection of data all of which is of the same type, such as list of name, list of temperature.
  5. 5. ARRAY DEFINITION Array’s element consist of memory allocation and identified by index. Array size : 91st Index Indexs 0 1 2 3 4 5 6 7 8
  6. 6.  Two types of arrays  One-dimensional array  Two-dimensional array
  7. 7. DECLARING ONE DIMENSIONALARRAY Will have a single row and can have any number of columns. Will have only one subscript. Subscript refers to the dimension of the array. Array declaration of 10 alphabet  type array_name[size]  Eg : char huruf[10];
  8. 8. INITIALIZING ONE DIMENSIONALARRAY Initialization is the process of assigning values to the array you have created. To assign initial values to each one of array’s elements we must enclose the values in curly braces ({ }) and separate them with comma (,).   Eg : char huruf[5] = {‘a’, ‘b’, ‘c’, ‘d’, ‘e’};
  9. 9. INITIALIZING ONE DIMENSIONALARRAY  Eg: int nombor[3] = {3, 24, 31}; first index 0 1 2 nombor 3 24 31 nombor[0];//3 nombor[1];//24 nombor[2];//31 nombor[0+1];//nombor[1];//24 nombor[3];
  10. 10. ACCESSING ELEMENT OF ONEDIMENSIONAL ARRAY Element is accessed by its index Array index refers to the location of the values in an array. The first element will always have the array index as 0.Syntax :<Variable name>[Array index] = Value;For example: marks[0]=95; marks[1]=85; marks[2]=75;
  11. 11. ACCESSING ELEMENT OF ONEDIMENSIONAL ARRAY Eg: int my_array[5] = {11, 22, 33, 44, 55}; to store the value 75 in the third element of my_array, we could write the following statement: my_array[2] = 75; to pass the value in 4th element of my_array and store the value into temporary variable, temp_value: int temp_value = my_array[3]; // also equals to 44
  12. 12. ACCESSING ELEMENT OF ONEDIMENSIONAL ARRAY if the name of an array is name, then name[0] is the name of the element that is in position 0, name[1] is the name of the element that is in position 1, etc. in general, the nth element is in position n-1. So if the array has n elements, their names are name[0], name[1], name[2], …, name[n- 1]. it is important to be able to clearly distinguish between the two uses that brackets [ ] have related to arrays: int name[5]; // declaration of a new array name[2] = 75; // access to an element of the array.
  13. 13. EXAMPLE Program Student_Marks.cpp will illustrate how to declare an array, initialize and access its elements.
  14. 14. #include<iostream>using namespace std;void main(){ marks[0] : 95 int marks[]={95,85,75,80,65}; marks[1] : 85 cout<<"marks[0] : "<<marks[0]; marks[2] : 75 marks[3] : 80 cout<<"nmarks[1] : "<<marks[1]; marks[4] : 65 cout<<"nmarks[2] : "<<marks[2]; cout<<"nmarks[3] : "<<marks[3]; cout<<"nmarks[4] : "<<marks[4];}
  15. 15. EXAMPLE Program Onedim_Int_Array.cpp illustrates how to initialize integer array and display its contents.
  16. 16. #include<iostream>using namespace std;void main(){ int y[4]={8,7,6,4}; for(int i=0;i<4;i++) { cout<<y[i]<<"n"; }}
  17. 17. EXAMPLE Program Onedim_Char_Array_Name.cpp illustrates how to initialize a character array and display its contents.
  18. 18. #include<iostream>using namespace std;void main(){ char stud_name[]={‘M,‘A,‘F,I,A}; for(int i=0;i<=4;i++) { cout<<stud_name[i]; }}
  19. 19. ENTERING DATA INTO AN ARRAY  When more number of values are to be stored in an array, a for loop can be used.  The sample code shows how to use a for loop in an array. for(int i=0;i<5;i++) { cout<<“Enter the marks: "; cin>>marks[i]; }
  20. 20. READING DATA FROM AN ARRAY You can use a for loop with a single cout statement to print the values from an array. for (int i=0;i<5;i++) { cout<<"Marks : "+marks[i]); }
  21. 21. EXAMPLE Program One_Int_Array.cpp illustrates how to accept five marks from the user and prints the values on the screen.
  22. 22. #include <iostream>using namespace std;void main(){ int marks[5]; //Accepting the marks for(int i=0;i<5;i++){ cout<<"Enter mark :"; cin>>marks[i]; } cout<<"nThe marks you have enter is"<<endl; //Displaying the array for(int i=0;i<5;i++){ cout<<"Marks:"<<marks[i]<<endl; }}
  23. 23. IN CLASS EXERCISE 4.1 Declare an array alpha of 15 elements of type int. Access the value of tenth element of array alpha. Set the value of fifth element of array alpha to 35. Set the value of ninth element of array alpha to the sum of fifth and sixth element of array alpha.
  24. 24.  Declare an array alpha of 15 elements of type int. int alpha [15]; Access the value of tenth element of array alpha. alpha [9]; Set the value of fifth element of array alpha to 35. alpha [4] = 35;
  25. 25.  Set the value of ninth element of array alpha to the sum of fifth and sixth element of array alpha. alpha [8] = alpha [4] + alpha [5]
  26. 26.  What is the output#include<iostream>using namespace std;void main(){ double num []= {2.0, 4.0, 6.5, 8.7}; cout<<num[1+2];}
  27. 27.  How to fill in value into array  Output: //program output #include <iostream> 1 using namespace std; 2 void main() 3 { 4 for(int i = 0; i < 10; ++i) 5 { 6 cout << i+1 << “n"; 7 } 8 } 9 10
  28. 28. #include <iostream>using namespace std;void main(){ int num[]={1,2,3,4,5,6,7,8,9,10}; for(int i = 0; i < 10; ++i) { cout << num[i]<< "n"; }}
  29. 29. TWO-DIMENSIONAL ARRAY Two-dimensional arrays can be described as "arrays of arrays". For example, a two-dimensional array can be imagined as a two-dimensional table made of elements of a same uniform data type.
  30. 30. PRESENTATION OF TWO-DIMENSIONAL ARRAY
  31. 31.  Assume that there are 5 students in a class and each of them study three different subjects, for example Mathematics, Physics and Chemistry.
  32. 32. Example int marks_table [5][3]; Syntax <Data type> <Variable name> [Row][Column];
  33. 33. TWO-DIMENSIONAL ARRAY Table jimmy represents a bidimensional array of 3 by 5 elements of type int. The way to declare this array in C++ would be: int jimmy [3][5]; column row
  34. 34. INITIALIZING TWO-DIMENSIONALARRAY Eg:  int array1[ 2 ][ 3 ] = { { 1, 2, 3 }, { 4, 5, 6 } };  Output: 123 456  int array2[ 2 ][ 3 ] = { 1, 2, 3, 4, 5 };  Output: 123 450  int array3[ 2 ][ 3 ] = { { 1, 2 }, { 4 } };  Output: 120 400
  35. 35. ACCESSING ELEMENT IN TWO-DIMENSIONAL ARRAY Element is accessed by the index of its row and column. Eg:  Toaccess the element in the 2nd row and at the 4th column of this two-dimentional array, we can used the following code: jimmy[1][3];
  36. 36. #include<iostream>using namespace std;void main(){ int array2[ 2 ][ 3 ] = {{ 1, 2, 3} ,{4, 5,6 }}; for(int index1=0;index1<2;index1++) { for(int index2=0;index2<3;index2++) cout<<array2[index1][index2] << " "; cout<<endl; }}
  37. 37. OUTPUT
  38. 38. WHAT IS OUTPUT?#include<iostream>using namespace std;void main(){ int marks_table[5][3] = {{83,99,74}, {88,90,72},{89,88,82}, {98,93,75},{78,60,65}}; cout<<marks_table[1][2]; }
  39. 39. #include<iostream>#include<string>using namespace std;void main(){string Data [2][3];//For first fowData[0][0] = "Lisa"; //lastnameData[0][1] = "Sulaiman"; //firstnameData[0][2] = "Kedah"; //location //Second row Data[1][0] = "Ali"; //lastname Data[1][1] = "Muhammad"; //firstname Data[1][2] = "Johor"; //location cout<<"LastnametFirstnametLocationn";for(int i=0;i<2;i++){ for(int j=0;j<3;j++){ cout<<Data[i][j]<<"tt"; } cout<<"n";//move to new line }}
  40. 40. #include <iostream>using namespace std;void main(){ int array2[ 23 ][ 4 ]; //Accepting the marks for (int row=0; row<2; row++) { for(int col=0; col<3; col++){ cout<<"Enter mark ["<<(row)<<"][" <<col <<"]: "; cin>>array2[row][col]; } cout<<endl; } //display for(int row=0; row<2; row++){ for(int col=0; col<3; col++) cout<<array2[row][col] << " "; cout<<endl; }}
  41. 41. OUTPUT
  42. 42. IN CLASS EXERCISE 4.2 Declare an array beta of 10 rows and 20 columns of type int. Examine the following: double values[ ] [ ] = { {1.2, 9.0, 3.2}, {9.2, 0.5, 1.5}, {7.3, 7.9, 4.8} } ; What is the value of values[2][1]?
  43. 43.  Which of the following statements constructs an array with 5 rows of 7 columns? long stuff[5][7]; long[5][7]; long stuff[7][5]; long [7][5];
  44. 44.  Declare an array beta of 10 rows and 20 columns of type int. int beta [10][20]o Value of values[2][1]? 7.9o long stuff[5][7];
  45. 45. SUMMARY An array is a structured data type with a fixed number of elements. Every element of an array is of the same type and can be accessed by their index. Array index started with 0. Array can be initialized during declaration. A one-dimensional array has one subscript. In two-dimensional array, elements are arranged in table form. To access element from two-dimensional array, pair of indices is needed (index for row and index for column).

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