Handout -17 Arrays of Strings, the break and continue statements

ICS 103: Computer Programming in C

Handout-17

Topic: Arrays of Strings, the break and continue statements.

Instructor: M. Waheed Aslam.

Objective:

· To know what are arrays of strings and how to use them

· To know the use of break and continue statements.

Arrays of strings:

To represent arrays of strings we need two-dimensional arrays. The first-dimension represents the number of strings in the array and the second-dimension represents the length of each string.

Example: #define LEN1 5

#define LEN2 81

char strarray [ LEN1 ] [ LEN2 ] = {“This”, “is”, “ICS103”, “Course”, “LEC”} ;

char str [LEN2] = {“Instructor”} ;

Here the array strarray is an array of 5 strings with the size of each string being 81.

Thus:

strarray [0] [0] = ‘T’, strarray [0] [1] = ‘h’, strarray [0] [2] = ‘i’,

strarray [0] [3] = ‘s’, strarray[0][4] = ‘\0’;

Similarly, strarray [4] [0] = ‘L’, strarray [4] [1] = ‘E’, strarray [4] [2] = ‘C’,

strarray[4][3] = ‘\0’.

The string arrays can be read by using gets( ) and printed by using puts( ) inside a for loop as

#include<stdio.h>

#include<string.h>

void main()

{

#define LEN1 5

#define LEN2 81

char strarray [ LEN1 ] [ LEN2 ];

int i;

printf("Please Enter 5 strings(Not having more than 80 characters)from Key board ");

for ( i = 0 ; i < 5 ; ++i )

{ printf ("\nEnter string number %d: ", i );

gets ( strarray [ i ] );

puts ( strarray [ i ] );

}

} // end of main

Interactive Session may be like this :

Use of break & continue statements:

The break Statement

· We have already met break in the discussion of the switch statement.

· It is used to exit from a loop or a switch, control passing to the first statement beyond the loop or a switch.

· With loops, break can be used to force an early exit from the loop, or to implement a loop with a test to exit in the middle of the loop body.

· A break within a loop should always be protected within an if statement which provides the test to control the exit condition.

Example:

#include<stdio.h>

void main()

{

int i;

for(i=1;i<=10;i++)

{

if(i==5)

break;

else

printf("%d\n",i);

}

printf("Best Wishes to you from your instructor, Najib Kofahi, ICS Dept. ");

} // end of main

Sample Output :

The continue Statement

· This is similar to break but is encountered less frequently.

· It only works within loops where its effect is to force an immediate jump to the loop control statement.

Ø In a while loop, jump to the test statement.

Ø In a do while loop, jump to the test statement.

Ø In a for loop, jump to the test, and perform the iteration.

· Like a break, continue should be protected by an if statement. You are unlikely to use it very often.