Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 211COSC 181 – Foundations of Computer ProgrammingClass 3327.4 Examples Using Arrays (Cont.)static local arrays and automatic local arrays•A static local variable in a function•Exists for the duration of the program•But is visible only in the function body•A static local array•Exists for the duration of the program•Is initialized when its declaration is first encountered•All elements are initialized to zero if not explicitly initialized•This does not happen for automatic local arrays31 // Fig. 7.13: f ig07_13.cpp2 / / Stat ic arrays are in it ia l i z e d to zero.3 #inc lude <iostream>4 using std::cout;5 using std::endl;67 void staticArrayInit( void ); // function prototype8 void automaticArrayInit( void ); // function prototype910 int main()11 {12 cout << "F ir s t call to each funct ion: \n";13 staticArrayInit();14 automaticArrayInit();1516 cout << "\n\nSecond call to each funct ion: \n";17 staticArrayInit();18 automaticArrayInit();19 cout << endl;2021 return 0; // indicates successful termination22 } // end mainOutlinefig07_13.cpp (1 of 3)42324 // funct ion to demonstrate a stat ic loca l array25 void staticArrayInit( void )26 {27 // initializes elements to 0 first time function is called28 static int array1[ 3 ]; // static local array 2930 cout << "\nVa lues on enter ing stat icArray In i t : \ n ";3132 // output contents of array133 for ( int i = 0; i < 3; i++ )34 cout << "array1[" << i << "] = " << array1[ i ] << " ";3536 cout << "\nValues on exiting staticArrayInit:\n";3738 // modify and output contents of array139 for ( int j = 0; j < 3; j++ )40 cout << "array1[" << j << "] = " << ( array1[ j ] += 5 ) << " ";41 } // end function staticArrayInit4243 // function to demonstrate an automatic local array44 void automaticArrayInit( void )45 {46 // initializes elements each time function is called 47 int array2[ 3 ] = { 1, 2, 3 }; // automatic local array4849 cout << "\n\nValues on entering automaticArrayInit:\n";Outlinefig07_13.cpp (2 of 3)Create a static array using keyword staticCreate an automatic local array55051 // output contents of array252 for ( int i = 0; i < 3; i++ )53 cout << "array2[" << i << "] = " << array2[ i ] << " ";5455 cout << "\nValues on exiting automaticArrayInit:\n";5657 // modify and output contents of array258 for ( int j = 0; j < 3; j++ )59 cout << "array2[" << j << "] = " << ( array2[ j ] += 5 ) << " ";60 } // end function automaticArrayInitFirst call to each function:Values on entering staticArrayInit:array1[0] = 0 array1[1] = 0 array1[2] = 0Values on exiting staticArrayInit:array1[0] = 5 array1[1] = 5 array1[2] = 5Values on entering automaticArrayInit:array2[0] = 1 array2[1] = 2 array2[2] = 3Values on exiting automaticArrayInit:array2[0] = 6 array2[1] = 7 array2[2] = 8Second call to each function:Values on entering staticArrayInit:array1[0] = 5 array1[1] = 5 array1[2] = 5Values on exiting staticArrayInit:array1[0] = 10 array1[1] = 10 array1[2] = 10Values on entering automaticArrayInit:array2[0] = 1 array2[1] = 2 array2[2] = 3Values on exiting automaticArrayInit:array2[0] = 6 array2[1] = 7 array2[2] = 8Outlinefig07_13.cpp (3 of 3)Values reflect changes from the previous function call – the array was not reinitialized67.5 Passing Arrays to FunctionsTo pass an array argument to a function•Specify array name without brackets•Array hourlyTemperatures is declared as int hourlyTemperatures[ 24 ];•The function call modifyArray( hourlyTemperatures, 24 );passes array hourlyTemperatures and its size to function modifyArray•Array size is normally passed as another argument so the function can process the specific number of elements in the array77.5 Passing Arrays to Functions (Cont.)Arrays are passed by reference•Function call actually passes starting address of array •So function knows where array is located in memory•Caller gives called function direct access to caller’s data•Called function can manipulate this data81 // Fig. 7.14: f ig07_14.cpp2 // Pass ing arrays and indiv idua l array elements to funct ions .3 #include <iostream>4 using std::cout;5 using std::endl;67 #include <iomanip>8 using std::setw;910 vo id modifyArray( int [], int ); // appears strange11 void modifyElement( int ); 1213 int main()14 {15 const int arraySize = 5; // size of array a16 int a[ arraySize ] = { 0, 1, 2, 3, 4 }; // initialize array a1718 cout << "Effects of passing entire array by reference:" 19 << "\n\nThe values of the original array are:\n";2021 // output original array elements22 for ( int i = 0; i < arraySize; i++ )23 cout << setw( 3 ) << a[ i ];2425 cout << endl;2627 // pass array a to modifyArray by reference28 modifyArray( a, arraySize ); 29 cout << "The values of the modified array are:\n";Outlinefig07_14.cpp (1 of 3)Declare 5-int array array with initializer list Function takes an array as argument Pass entire array to function modifyArray93031 / / output modif ied array elements32 for ( int j = 0; j < arraySize; j++ )33 cout << setw( 3 ) << a[ j ];3435 cout << "\n\n\nEffects of passing array element by value:"36 << "\n\na[3] before modifyElement: " << a[ 3 ] << endl;3738 modifyElement( a[ 3 ] ); // pass array element a[ 3 ] by value39 cout << "a[3] after modifyElement: " << a[ 3 ] << endl;4041 return 0; // ind ica t es success fu l terminat ion42 } // end main4344 // in funct ion modifyArray, "b" point s to the orig ina l array "a" in memory45 void modifyArray( int b[], int sizeOfArray ) 46 { 47 // multiply each array element by 2 48 for ( int k = 0; k < sizeOfArray; k++ ) 49 b[ k ] *= 2; 50 } // end function modifyArray Outlinefig07_14.cpp (2 of 3)Pass array element a[ 3 ] to function modifyElement Function modifyArray manipulates the array directly105152 / / in funct ion modifyE lement, "e" is a loca l copy of 53 // array element a[ 3 ] passed from main