“指针和整数”之间的比较 [英] Comparison between "Pointer and Integer"
问题描述
我正在尝试比较IF中的指针和整数。声明
如何使这项工作？
if（patient [index] .id！= NULL）{
}
谢谢
克里斯
I''m trying to compare between pointer and integer in an "IF" statement
how do I make this work?
if(patient[index].id != NULL){
}
Thanks
Chris
推荐答案
ch****@gmail.com 写道：
我正在尝试比较IF中的指针和整数。声明
如何使这项工作？
if（patient [index] .id！= NULL）{
}
I''m trying to compare between pointer and integer in an "IF" statement
how do I make this work?
if(patient[index].id != NULL){
}
为什么你认为它不是？
-
Ian Collins。
Why do you think its doesn''t?
--
Ian Collins.
" ch **** @ gmail.com" < ch **** @ gmail.comwrites：
"ch****@gmail.com" <ch****@gmail.comwrites:
我正在尝试比较IF中的指针和整数。声明
如何使这项工作？
if（patient [index] .id！= NULL）{
}
I''m trying to compare between pointer and integer in an "IF" statement
how do I make this work?
if(patient[index].id != NULL){
}
为什么要比较指针和整数？
什么是id ？如果它是一个指针，上面应该工作。如果它是一个
整数，将它与NULL进行比较是没有意义的。
发布一个小的，完整的程序说明是有帮助的你的
问题。如果你有一个编译程序，请告诉我们你的编译器给你的确切的
错误信息。另外，你的样本应该可以单独编译。
-
Keith Thompson（The_Other_Keith） ks *** @ mib.org < http://www.ghoti.net/~kst>
圣地亚哥超级计算机中心< *< http://users.sdsc.edu/~kst>
"我们必须做点什么。这是事情。因此，我们必须这样做。
- Antony Jay和Jonathan Lynn，是部长
Why would you want to compare a pointer and an integer?
What is "id"? If it''s a pointer, the above should work. If it''s an
integer, comparing it to NULL makes no sense.
It''s helpful to post a small, complete program that illustrates your
problem. If you''re having a compilation program, show us the exact
error message your compiler gives you. Otherise, your sample should
be compilable by itself.
--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
5月27日，22日：45，Keith Thompson< k ... @ mib.orgwrote：
On 27 May, 22:45, Keith Thompson <k...@mib.orgwrote:
" chu ... @ gmail.com" < chu ... @ gmail.comwrites：
"chu...@gmail.com" <chu...@gmail.comwrites:
我正在尝试比较IF中的指针和整数。声明
I''m trying to compare between pointer and integer in an "IF" statement
如何使这项工作？
how do I make this work?
if（patient [index] .id！= NULL）{
}
if(patient[index].id != NULL){
}
为什么要比较指针和整数？
什么是id？如果它是一个指针，上面应该工作。如果它是一个
整数，将它与NULL进行比较是没有意义的。
发布一个小的，完整的程序说明是有帮助的你的
问题。如果你有一个编译程序，请告诉我们你的编译器给你的确切的
错误信息。另外，你的样本应该可以自行编译。
-
Keith Thompson（The_Other_Keith）k ... @ mib.org< http://www.ghoti.net/~kst>
圣地亚哥超级计算机中心< *< http://users.sdsc.edu/~kst>
我们必须做点什么。这是事情。因此，我们必须这样做。
- Antony Jay和Jonathan Lynn，是部长
Why would you want to compare a pointer and an integer?
What is "id"? If it''s a pointer, the above should work. If it''s an
integer, comparing it to NULL makes no sense.
It''s helpful to post a small, complete program that illustrates your
problem. If you''re having a compilation program, show us the exact
error message your compiler gives you. Otherise, your sample should
be compilable by itself.
--
Keith Thompson (The_Other_Keith) k...@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
ok ..
#include< stdio.h>
#include< ; stdlib.h>
#include< time.h>
#include< string.h>
＃定义MAXPATIENTS 20
struct details {
int id;
char forename [20];
char initial;
char surname [20];
int day_of_entry;
int max_wait;
};
//列出个别患者信息 - 正在进行工作
int list_patient（int index）{
int time_left = 0;
int x = 0;
int i;
//应检查索引是否指向记录，
//否则它应该返回-1 !!
if（patient [index] .id！= NULL）{
printf（" Patient）详情：\ n"）;
printf（" ID：％d |"，patient [index] .id）;
printf（" Name： ％s"，patient [index] .forename）;
printf（"％c"，patient [index] .in itial）;
printf（"％s |"，patient [index] .surname）;
printf（" Days on queue％d |"， day_now（） - 患者[指数] .day_of_entry）;
printf（最长等待天数％d \ n，time_left =
患者[指数] .max_wait - （day_now（） - patient [i] .day_of_entry））;
}
else {
x = -1;
}
返回x;
}
int main（无效）{
list_patient（0）;
返回0;
}
ok..
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#define MAXPATIENTS 20
struct details {
int id;
char forename[20];
char initial;
char surname[20];
int day_of_entry;
int max_wait;
};
//Lists individual patient information -Work in Progress
int list_patient(int index){
int time_left = 0;
int x = 0;
int i;
//Should check if index points to a record,
//Or else it should return -1!!
if( patient[index].id != NULL){
printf("Patient Details: \n");
printf("ID: %d |",patient[index].id);
printf("Name: %s ",patient[index].forename);
printf("%c ",patient[index].initial);
printf("%s |",patient[index].surname);
printf("Days on queue %d |",day_now()- patient[index].day_of_entry);
printf("Maximum waiting days %d \n",time_left =
patient[index].max_wait - (day_now() - patient[i].day_of_entry));
}
else {
x = -1;
}
return x;
}
int main(void){
list_patient(0);
return 0;
}
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