C语言-用户登录系统

青旅半醒 2023-06-29 05:53 15阅读 0赞

运行程序时，指定用户名，不输入，或少输入，或输入错误，都提示用户不同的错误，并退出程序。  
用户名正确：开始输入密码（要求错误后能多次输入，循环）。  
密码输入错误：重新输入（错误5次结束程序）。  
输入正确：打印欢迎用户！  
更多资料请点击：[我的目录][Link 1]

运行时输入用户名与密码：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ_size_16_color_FFFFFF_t_70]

#include <stdio.h>
    #include <string.h>
    
    int main(int argc , const char **argv)
    { 	
    	char name[10];
    	char word[10];
    	char username[10] = "jiajia"; 
    	char password[10] = "jiajia";
    	int n;
    
    	printf("\n\n");
    	printf("\t*******************************\n");
    	printf("\t********* 用户登录系统 *********\n");
    	printf("\t*******************************\n");
    	printf("\n\n");
    
    	printf("\tPlease enter username.\n");	
    	printf("\tusername:");
    	scanf("%s",name);
    	printf("\n");
    	
    		if( strcmp(username , name) == 0)
    		{ 
    			printf("\tPlease enter password.\n");
    			printf("\tpassword:");
    			scanf("%s",word);
    			for(n = 0; n < 5; n++)
    			{ 
    				if( strcmp( password , word) == 0 )
    				{ 				
    					printf("\n\n");
    					printf("\t*******************************\n");
    					printf("\t********* 欢迎用户！ *********\n");
    					printf("\t*******************************\n");
    					printf("\n\n");
    					break;
    				}
    				else
    				{ 
    					printf("\tPlease enter again!\n");
    					printf("\tpassword:");
    					scanf("%s",word);
    					if( strcmp( password , word) == 0 )
    					{ 				
    						printf("\n\n");
    						printf("\t*******************************\n");
    						printf("\t********* 欢迎用户！ *********\n");
    						printf("\t*******************************\n");
    						printf("\n\n");
    						break;
    					}
    				}
    			}	
    		}
    		else if( strlen( name ) < 6)
    		{ 	
    			printf("\tLess input!\n");
    		}
    		else if( strcmp(username , name) != 0)
    		{ 	
    			printf("\tUsername error! Please enter again!\n");
    		}
    	return 0;
    }

基于Linux系统shell输入：（需要在运行前输入用户名）  
![在这里插入图片描述][20200110200837971.png]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ_size_16_color_FFFFFF_t_70 1]

#include <stdio.h>
    #include <string.h>
    
    int main(int argc , const char **argv)
    { 	
    	char username[10] = "jiajia"; 
    	char password[10] = "jiajia";
    	char word[10];
    	int n;
    
    	printf("\n\n");
    	printf("\t*******************************\n");
    	printf("\t********* 用户登录系统 *********\n");
    	printf("\t*******************************\n");
    	printf("\n\n");
    	
    		if( strcmp(username , argv[1]) == 0)
    		{ 	
    			printf("\tUsername:\t%s\n",argv[1]);
    			printf("\tPlease enter password.\n");
    			printf("\tPassword:\t");
    			scanf("%s",word);
    			for(n = 0; n < 5; ++n)
    			{ 
    				if( strcmp( password , word) == 0 )
    				{ 	
    					printf("\n\n");			
    					printf("\t*******************************\n");
    					printf("\t********* 欢迎用户！ *********\n");
    					printf("\t*******************************\n");
    					printf("\n\n");
    					break;
    				}
    
    				else
    				{ 
    					printf("\n\tPlease enter again!\n");
    					printf("\tpassword:\t");
    					scanf("%s",word);
    					if( strcmp( password , word) == 0 )
    					{ 	
    						printf("\n\n");			
    						printf("\t*******************************\n");
    						printf("\t********* 欢迎用户！ *********\n");
    						printf("\t*******************************\n");
    						printf("\n\n");
    						break;
    					}
    				}
    			}	
    		}
    
    		else if( strlen( argv[1] ) < 6)
    		{ 	printf("\tUsername:\t%s\n",argv[1]);
    			printf("\tLess input!\n");
    		}
    
    		else if( strcmp(username , argv[1]) != 0)
    		{ 	printf("\tUsername:\t%s\n",argv[1]);
    			printf("\tPlease enter again!\n");
    		}
    	return 0;
    }

更多资料请点击：[我的目录][Link 1]

[Link 1]: http://note.youdao.com/noteshare?id=1370b0e8f4a16b80e7dede7836df3c08
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200110202248704.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ==,size_16,color_FFFFFF,t_70
[20200110200837971.png]: https://img-blog.csdnimg.cn/20200110200837971.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200110200735232.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc5MzE4MQ==,size_16,color_FFFFFF,t_70