t11AArraysDeclarations

t11AArraysDeclarations - Arrays Declarations...

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Unformatted text preview: Arrays Declarations www.kite-legends.blogspot.com Dale Roberts Arrays Array Group of consecutive memory locations Group Same name and type, ex: an array of integers Same Name of array (Note that all elements of this array have the same name, my_array) -45 6 0 72 1543 -89 0 62 -3 1 6453 78 To refer to an element, specify Array name Position number of particular element in the array my_array[0] my_array[1] my_array[2] my_array[3] my_array[4] my_array[5] my_array[6] my_array[7] my_array[8] my_array[9] Format: First element at position 0 First n element array named c: array_name[ position number ] position c[ 0 ], c[ 1 ]...c[ n – 1 ] c[ c[ Example: int my_array[12] int my_array[0]= -45 ⇐ value stored value Example: Position number must be an integer number or an my_array[10] integer expression my_array[11] my_array[1.5] ⇐ ERROR!! ERROR!! my_array[i+j] ⇐ valid if i and j are integers valid are Position number of the element within array my_array www.kite-legends.blogspot.com Dale Roberts Arrays (cont.) Arrays (cont.) Array elements are like normal variables my_array[8] = -3; -3; scanf("%d", &my_array[8]); printf("%d",my_array[8]); scanf("%d", Perform operations in subscript. If x equals 3: Perform my_array[ 5 - 2 ] == my_array[ 3 ] == my_array[ x ] my_array[ Declaring Arrays When declaring arrays, specify Name Type of array Number of elements: arrayType Number arrayName[numberOfElements]; arrayName[numberOfElements]; Examples: int c[ 100 ]; /* reserve memory sufficient enough to store 100 int elements of type integer */ elements float myArray[ 3284 ]; float www.kite-legends.blogspot.com Dale Roberts Arrays (cont.) Arrays (cont.) Declaring multiple arrays of same type: format similar to regular variables format Declaring Example: int b[ 100 ], x[ 27 ]; int Arrays may be declared to contain other data types Arrays Example: int a[ 100 ]; float b[ 100 ]; char c[ 100 ]; /* Strings are stored by using character arrays char Strings */ */ Example: #include <stdio.h> #include /* a simple program that uses arrays */ main( { int i, array_int[100]; for (i=0; i<100; i++) array_int[i]=0; for (i=0; i<100; i++) printf(“element %d: %d\n”, i, array_int[i]); } www.kite-legends.blogspot.com Dale Roberts Arrays (cont.) Arrays (cont.) Initializers int n[5] = {1, 2, 3, 4, 5}; int Example: main() Example { int i, a[10]={1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; for (i=0; i<10; i++) printf(“Element: %d\n”, a[i]); } If there are fewer initializations than elements in the array, then the If remaining elements are automatically initialized to 0. 0. int n[5] = {0} /* All elements 0 */ All int a[10] = {1, 2} /* a[2] to a[9] are initialized to zeros a[9] */ */ int b[5] = {1, 2, 3, 4, 5, 6} /* syntax error */ /* syntax C arrays have no bounds checking If size omitted, initializers determine it int n[ ] = { 1, 2, 3, 4, 5 }; int */ */ /* 5 initializers, therefore 5 element array Scalable Arrays: a better programming style #define SIZE 10 int c[SIZE]; /* defines a symbolic constant size with value 10 */ www.kite-legends.blogspot.com Dale Roberts Arrays (cont.) Arrays (cont.) Example: #include <stdio.h> #define SIZE 100 main() { int i, a[SIZE]; int sum = 0; … for (i=0; i < SIZE; i++) sum = sum + a[i]; printf(“sum: %d\n, sum); } www.kite-legends.blogspot.com Dale Roberts 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 /* Fig. 6.8: fig06_08.c Histogram printing program */ #include <stdio.h> #define SIZE 10 int main() { int n[ SIZE ] = { 19, 3, 15, 7, 11, 9, 13, 5, 17, 1 }; int i, j; printf( "%s%13s%17s\n", "Element", "Value", "Histogram" ); for ( i = 0; i <= SIZE - 1; i++ ) { printf( "%7d%13d ", i, n[ i ]) ; for ( j = 1; j <= n[ i ]; j++ ) printf( "%c", '*' ); printf( "\n" ); } return 0; } /* print one bar */ 1. Initialize array 2. Loop 3. Print Program output Element 0 1 2 3 4 5 6 7 8 9 Value 19 3 15 7 11 9 13 5 17 1 Histogram ******************* *** *************** ******* *********** ********* ************* ***** ***************** * www.kite-legends.blogspot.com Dale Roberts ...
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This note was uploaded on 12/08/2010 for the course CSE 2017 taught by Professor Kittu during the Spring '10 term at APIIT.

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