C goto statement magic jump tool or dangerous bomb?

Introduction:

C language is a very flexible and powerful programming language, which provides a lot of statements to control the process, such as if, switch, for, while, do-while, etc., which allows us to execute different ** according to different conditions and logic. However, there is a special kind of statement in C that allows us to jump to a specified position in the program at will, and that is the goto statement.

Definition of a goto statement

The goto statement, also known as the unconditional transfer statement, is used to make the execution process of a program jump from the current position to another location within the same function, which is identified by a label.

The general format of a goto statement is as follows:

goto label;Jump to tabs....Other label: label statement;The statement that is executed after the jump

Usage of goto statements

The usage of the goto statement is very simple, as long as you write the goto label where you need to jump, and then write the label: at the destination of the jump, you can achieve an unconditional jump. For example, the following program can implement a function similar to a while loop, outputting numbers from 1 to 10:

#include int main() return 0; }

As you can see, the program achieves the effect of a loop through the goto statement and the if statement, and each loop will output the value of i, and then judge whether i is less than or equal to 10, if so, jump to the loop to continue the loop, otherwise, end the loop.

Advantages and disadvantages of goto statements

The advantages of goto statements: they can allow us to flexibly control the execution process in the program, sometimes simplify some complex logic, and improve the readability and efficiency of the program. For example, the following program can be implemented to find an element in a two-dimensional array, and if it does, it jumps out of the double-layer loop, otherwise, it continues to look:

include define n 3 to define the number of rows of the array define m 4 to define the number of columns of the array int main() to define a two-dimensional array int x = 7;Define the element int i, j;to findDefine the loop variable int found = 0;Define a flag variable that indicates whether for (i = 0;) is found i < n;i++) iterate through each row of the array }out: define a tag out if (found) if else is found if return 0 is not found }

It can be seen that the program realizes the function of jumping out in the double-layer loop through the goto statement, which avoids the use of additional variables to control the end condition of the loop, making ** more concise and clear.

However, the disadvantage of the goto statement is also obvious, that is, it can break the structure and logic of the program, make the program difficult to understand and maintain, and even cause some potential errors and risks. Therefore, many programming books and teachers do not recommend using goto statements, but recommend using other control process statements instead.

Summary

The goto statement is a special statement in the C language, which allows the program to jump to the specified position without any conditions, sometimes it can simplify some complex logic, improve the readability and efficiency, but it may also destroy the structure and logic of the program, making the program difficult to understand and maintain, and even cause some potential errors and risks. Therefore, we should be careful when using goto statements, try to avoid abuse, and try to use other control process statements instead.

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