1. Lecture-5
Arrays

2. Declaration
Analogous to using subscripted variables used in mathematical notations e.g. a1, a2, a3,….an
Declared using the [] notation to indicate the range/size of the array
Elements are indexed using the [] notation, ranging from 0 to one less than the bound

3. Example #include <stdio.h> int main() {
Representation of array in program memory
#include <stdio.h>
int main() {
int a=0, b[5], c=0, cnt=0;
for(cnt=0;cnt<5;cnt++) {
b[cnt]=cnt; }
return 0; a
b[0]
b[1]
b[2]
b[3]
b[4] c
Memory
Follow this link to arr-rev.c

4. Arrays Operations
There are no built-in operations on arrays e.g. you cannot write a+b, to add two arrays a[] and b[]
Functions cannot return arrays by value
To pass or return the same array, you have to pass by reference
Follow this link to ref-arr.c

5. In-class exercise 5-1 Write a program to:
Create array a[5], and take in 5 values from the user to populate the array
Create array b[5], and take in 5 values from the user to populate the array
Create a third array c[5], add values of variables in a[] and b[] and store results in c[] i.e. C[] = a[] + b[]

6. Multidimensional Arrays
Declared with one or more bracketed subscripts e.g. a[][]
For function declarations, only the first index may omit the bounds e.g.
void addArray(float a[][2], float cnt);

7. Strings (string.h)
Strings are arrays with elements of type character or ‘char’
Strings are always terminated with a end-of-line control character: \n
Internally strings are stored with ASCII integer values of the character which they represent

8. String operations
gets() reads a line as a string(array of characters) from the console. Return value is the string or NULL
puts() writes a string to the console
strlen(): Number of characters in a
strcmp(a,b): compare strings a and b
strcpy(a, b): copy b into a

9. Example
Follow this link to str-cmp.c