我正在尝试在用户键入“退出”或“退出”时使while - do
循环退出。由于某种我无法理解的原因,我根本无法实现。如果我分别应用这些条件之一,则效果很好,但我需要同时拥有两个条件。
我在线搜索,甚至在不同的编程语言上也找到了几个示例,例如(PHP)Do-While Loop with Multiple Conditions,(Python)How to do while loops with multiple conditions,(C ++)Using multiple conditions in a do…while loop] >等。但是无论我遵循什么程序,我都可以使其同时在两种条件下工作。
理想的解决方案是也添加大写条件,但是一旦解决此问题,我便可以稍后使用。
也许有一双新鲜的眼睛看到我缺少的东西。
代码示例如下:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_CHARACTERS 250
#define MAX_USERNAME 12
#define MAX_USERS 1024
#define MIN_REQUIRED 3
#define MAX_PORT 65536
#define MIN_PORT 1
typedef struct rec {
char username[MAX_USERNAME];
char msg[MAX_CHARACTERS];
}RECORD;
/* Usage Instructions void because we do not have any return */
int help(void) {
printf("Usage: test.c [-s <arg0>] [-s <arg1>]\n");
printf("\t-s: a string program name <arg0>\n");
printf("\t-s: a string with a Nickname maximum characters %i <arg2>\n",MAX_USERNAME);
return (1);
}
int main(int argc, char **argv) {
if ( argc < MIN_REQUIRED ) {
printf ("Please follow the instructions: not less than %i argument inputs\n", MIN_REQUIRED);
return help();
}
else if ( argc > MIN_REQUIRED ) {
printf ("Please follow the instructions: not more than %i argument inputs\n", MIN_REQUIRED);
return help();
}
else {
RECORD *ptr_record;
ptr_record = (RECORD *) malloc (sizeof(RECORD));
if (ptr_record == NULL) {
printf("Out of memory!\nExit!\n");
exit(0);
}
char username_argv[MAX_USERNAME];
memset( username_argv, '\0', sizeof(username_argv) );
if (strlen(argv[2]) > 12 ) {
printf("Maximum characters for Nickname: %i\nPlease try again!\n", MAX_USERNAME);
exit(0);
}
strcpy( username_argv, argv[1] );
strncpy( (*ptr_record).username, username_argv, sizeof(username_argv) );
printf("Username pointer: %s\n", (*ptr_record).username);
do {
printf("Please enter your MSG: \n");
scanf ("%s", (*ptr_record).msg);
printf("User MSG: %s\n", (*ptr_record).msg);
//} while ((strcmp((*ptr_record).msg,"exit") != 0) || (strcmp((*ptr_record).msg, "quit") != 0));
//} while (strcmp((*ptr_record).msg, "exit") || strcmp((*ptr_record).msg, "quit") != 0);
//} while ((strcmp((*ptr_record).msg,"exit")) || (strcmp((*ptr_record).msg, "quit")) != 0);
//} while ((*ptr_record).msg != "quit" || (*ptr_record).msg != "exit");
} while (((*ptr_record).msg != exit) || ((*ptr_record).msg != ));
free(ptr_record);
return 0;
} /* End of else */
} /* End of main() */
我正在尝试一段时间-当用户键入“退出”或“退出”时,do循环退出。由于某种我无法理解的原因,我根本无法实现。如果我应用以下条件之一...
尝试:
[这不起作用,因为您要执行的操作是DO
循环WHILE
字符串不同于"exit"
AND
字符串不同于"quit"
。
示例中的所有行都使用逻辑OR运算符||
来测试这两个条件。您是否尝试过逻辑AND运算符&&?
尝试一下。您应该使用&&运算符,因为两个条件都必须为真才能继续。