Preface

What this article records is C In language goto knowledge .

One 、goto Usage of

goto The usage of is to change the order of program execution , Jump from somewhere to the place you sign .
An example I encountered in a real application scenario is ： The program encounters an error and jumps to the specified flag to execute the code （ Print error messages , Then end the function ）

Two 、 Sample code

1. Conditions established , Direct jump

The code is as follows （ Example ）：

#include<stdio.h>

int main() {
    
	int c = 1;
	if (c > 0) {
    
		goto start;
	}
	printf(" power 1\n");
	printf(" example 2\n");
	printf(" example 3\n");

start:	
	printf(" example 4\n");
	printf(" example 5\n");

}

result ：if Conditions established , Jump directly to start sign , Output instance 4 And examples 5. example 1、2、3 Don't execute .

2. Conditions not established

The code is as follows （ Example ）：

#include<stdio.h>

int main() {
    
	int c = 1;
	if (c < 0) {
    
		goto start;
	}
	printf(" power 1\n");
	printf(" example 2\n");
	printf(" example 3\n");

start:	
	printf(" example 4\n");
	printf(" example 5\n");

}

result ： Output instance 12345, because if Conditions not established , Then execute in sequence , Instance executed 123 in the future ,start It's just a sign , So the program will still be executed . Unless you are outputting instances 3 Add a return, Then do not execute the instance 45.