C has a goto statement which permits unstructured jumps to be made. To use a goto statement, you simply use the reserved word goto followed by the symbolic name to which you wish to jump. You can jump nearly anywhere within a function, but you are not permitted to jump into a loop

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The goto Statement

C has a goto statement which permits unstructured jumps to be made. To use a goto statement, you simply use the reserved word goto followed by the symbolic name to which you wish to jump. The name is then placed anywhere in the program followed by a colon. You can jump nearly anywhere within a function, but you are not permitted to jump into a loop, although you are allowed to jump out of a loop.

This particular program is really a mess but it is a good example of why software writers are trying to eliminate the use of the goto statement as much as possible. The only place in this program where it is reasonable to use the goto is, where the program jumps out of the three nested loops in one jump. In this case it would be rather messy to set up a variable and jump successively out of each of the three nested loops but one goto statement gets you out of all three in a very concise manner.

Some persons say the goto statement should never be used under any circumstances, but this is narrow minded thinking. If there is a place where a goto will clearly do a neater control flow than some other construct, feel free to use it, however, as it is in the rest of the program on your monitor. Let us see the example:

#include <stdio.h>

int main()
{
int dog, cat, pig;

goto real_start;

some_where:

printf("This is another line of the mess.\n");

goto stop_it;

/* the following section is the only section with a useable goto */
real_start:

for(dog = 1 ; dog < 6 ; dog = dog + 1)
{

for(cat = 1 ; cat < 6 ; cat = cat + 1)
{

for(pig = 1 ; pig < 4 ; pig = pig + 1)
{
printf("Dog = %d Cat = %d Pig = %d\n", dog, cat, pig);

if ((dog + cat + pig) > 8 ) goto enough;
}
}
}

enough: printf("Those are enough animals for now.\n");
/* this is the end of the section with a useable goto statement */

printf("\nThis is the first line of the code.\n");
goto there;

where:
printf("This is the third line of the code.\n");
goto some_where;

there:
printf("This is the second line of the code.\n");
goto where;

stop_it:
printf("This is the last line of this mess.\n");
return 0;
}

Let us see the results displayed

Dog = 1 Cat = 1 Pig = 1
Dog = 1 Cat = 1 Pig = 2
Dog = 1 Cat = 1 Pig = 3
Dog = 1 Cat = 2 Pig = 1
Dog = 1 Cat = 2 Pig = 2
Dog = 1 Cat = 2 Pig = 3
Dog = 1 Cat = 3 Pig = 1
Dog = 1 Cat = 3 Pig = 2
Dog = 1 Cat = 3 Pig = 3
Dog = 1 Cat = 4 Pig = 1
Dog = 1 Cat = 4 Pig = 2
Dog = 1 Cat = 4 Pig = 3
Dog = 1 Cat = 5 Pig = 1
Dog = 1 Cat = 5 Pig = 2
Dog = 1 Cat = 5 Pig = 3

Those are enough animals for now.

This is the first line of the code.
This is the second line of the code.
This is the third line of the code.
This is another line of the mess.
This is the last line of this mess.


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Data Recovery Book
 
Chapter 1 An Overview of Data Recovery
Chapter 2 Introduction of Hard Disks
Chapter 3 Logical Approach to Disks and OS
Chapter 4 Number Systems
Chapter 5 Introduction of C Programming
Chapter 6 Introduction to Computer Basics
Chapter 7 Necessary DOS Commands
Chapter 8 Disk-BIOS Functions and Interrupts Handling With C
Chapter 9 Handling Large Hard Disks
Chapter 10 Data Recovery From Corrupted Floppy
Chapter 11 Making Backups
Chapter 12 Reading and Modifying MBR with Programming
Chapter 13 Reading and Modifying DBR with Programming
Chapter 14 Programming for “Raw File” Recovery
Chapter 15 Programming for Data Wipers
Chapter 16 Developing more Utilities for Disks
Appendix Glossary of Data Recovery Terms
 
 

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