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:
int dog, cat, pig;
printf("This is another line of the mess.\n");
/* the following section is the only section with a useable goto */
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");
printf("This is the third line of the code.\n");
printf("This is the second line of the code.\n");
printf("This is the last line of this mess.\n");
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.
|Sample Chapters from book DATA RECOVERY WITH AND WITHOUT PROGRAMMING by Author Tarun Tyagi
Publishers of the Book
Number of Pages
Price of the Book
BPB Publications, New Delhi, India
$69.00 (Including Shipping Charges, Cost of Book and Other expenses, Free Source Code CD included with the Book)