在我第一次打印printf打印出副本之后，然后将它的哺乳动物指针改为giberish。因此，当它在第二个循环内打印时，第一个哺乳动物出来很好但是然后列表中的下一个丢失了。然后，每次退出该循环时，列表中的下一个副本都将丢失。
void print_list3() {
Duplicate *next=head3.duppointer;
int i,j;
for(i=0;i<list_length3;i++) {
printf("%c %d %f %f\n",next->species,next->number_of,next->location.lat,next->location.lng);
Mammal mam;
mam=*next->mampointer;
for(j=0;j<next->number_of;j++) {
printf(" %f %f %s\n",mam.location.lat,mam.location.lng,mam.observer.id);
if (mam.pointer!=NULL) {
mam=*mam.pointer;
}
}
if (next!=NULL) {
next=next->duppointer;
}
}
}
编辑：决定将我的所有代码放在这里，也许你们更容易找到这个bug。问题出在功能2上。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "navigation.h"
#include "Mainheader.h"
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <math.h>
int list_length1=0;
int list_length2=0;
int list_length3=0;
Observer head1;
Mammal head2;
Duplicate head3;
/*
*
*/
int main(int argc, char** argv) {
int choice=0;
run_menu();
scanf("%d",&choice);
while(choice<1 || choice>4) {
printf("Invalid choice\n");
scanf("%d",&choice);
}
if(choice==1) {
function1();
}
else if(choice==2) {
function2();
}
else if(choice==3) {
function3();
}
else if(choice==4) {
printf("Exiting!");
}
return (EXIT_SUCCESS);
}
void run_menu() {
printf("1 - Display cetacean Mammals fn1\n"
"2 - Display without duplicates fn2\n"
"3 - Display Pods without duplicates fn3\n"
"4 - Exit\n");
}
void function1(){
int i=0;
get_directories();
Mammal *next;
next=head2.pointer;
for(i=0;i<list_length2;i++) {
location_calculator(next);
if (next!=NULL) {
next=next->pointer;
}
}
print_reallist();
}
void function2(){
int i=0;
get_directories();
Mammal *next;
next=head2.pointer;
for(i=0;i<list_length2;i++) {
location_calculator(next);
if (next!=NULL) {
next=next->pointer;
}
}
remove_duplicates();
print_list3();
}
void function3(){
}
char get_directories() {
char file1[256];
char file2[256];
char obsid[5];
TD td;
FILE *file_no1;
FILE *file_no2;
Observer* obs=malloc(sizeof(*obs));
Mammal* mam=malloc(sizeof(*mam));
//printf("Please Enter Observer File Path: ");
//scanf("%s",&file1);
strcpy(file1,"/ceri/homes1/j/jsc12/CS237/Assignment/cetaceans/data/observers_2.txt");
file_no1=fopen(file1, "r");
fscanf(file_no1,"%d%d%d%d%d%d",&td.day,&td.month,&td.year,&td.hour,&td.minute,&td.second);
while(fscanf(file_no1,"%s%lf%lf",obs->id,&obs->location.lat,&obs->location.lng)==3) {
obs->timedate=td;
Observer *new;
new=create_observer(obs->id,obs->location,obs->timedate);
add_observer(new);
}
fclose(file_no1);
//printf("Please Enter Sighting File Path: ");
//scanf("%s",&file2);
strcpy(file2,"/ceri/homes1/j/jsc12/CS237/Assignment/cetaceans/data/sightings_2.txt");
file_no2=fopen(file2, "r");
while(fscanf(file_no2,"%4s %c %lf%lf",&obsid,&mam->species,&mam->bearing,&mam->range)==4) {
Observer* obs2=find_observer(obsid);
mam->observer=*obs2;
Mammal *new;
new=create_mammal(mam->observer,mam->species,mam->bearing,mam->range);
add_mammal(new);
}
fclose(file_no2);
}
Mammal* create_mammal (Observer obs,char spec,double bear,double ran){
Mammal* b=malloc(sizeof *b);
b->observer=obs;
b->species=spec;
b->bearing=bear;
b->range=ran;
b->pointer=NULL;
return b;
}
void add_mammal (Mammal *n){
n->pointer=head2.pointer;
head2.pointer=n;
list_length2++;
}
Duplicate* create_duplicate (Duplicate* d){
Mammal mam;
int i;
location average;
average.lat=0;
average.lng=0;
mam=*d->mampointer;
Duplicate* b;
b=malloc(sizeof *b);
b->species=d->mampointer->species;
b->number_of=d->number_of;
for(i=0;i<d->number_of;i++) {
average.lat+=mam.location.lat;
average.lng+=mam.location.lng;
if (mam.pointer!=NULL) {
mam=*mam.pointer;
}
}
average.lat/=d->number_of;
average.lng/=d->number_of;
b->location=average;
b->mampointer=d->mampointer;
b->duppointer=NULL;
return b;
}
void add_duplicate (Duplicate *n){
n->duppointer=head3.duppointer;
head3.duppointer=n;
list_length3++;
}
Observer* create_observer (char id[5],location locat,TD timdat){
Observer* b=malloc(sizeof *b);
strcpy(b->id,id);
b->location=locat;
b->timedate=timdat;
b->pointer=NULL;
return b;
}
void add_observer (Observer *n){
n->pointer=head1.pointer;
head1.pointer=n;
list_length1++;
}
Observer* find_observer(char id[5]) {
Observer *next=head1.pointer;
int i=0;
while(i<list_length1) {
if(strcmp(id,next->id)==0) {
return(next);
}
next=next->pointer;
i++;
}
}
void location_calculator(Mammal* m) {
double obslat=m->observer.location.lat;
double obslng=m->observer.location.lng;
double rbear=(m->bearing*M_PI)/180;
m->location.lat=obslat+(m->range*cos(rbear))/60;
m->location.lng=obslng+(m->range*sin(rbear)/cos((obslat*M_PI)/180))/60;
}
void print_reallist() {
Mammal *next=head2.pointer;
int i;
printf("|==========|==========|==========|==========|\n");
printf("|%-10s|%-10s|%-10s|%-10s|\n","Longitude","Latitude","Species","Observer");
printf("|==========|==========|==========|==========|\n");
for(i=0;i<list_length2;i++) {
if (next->species=='P') {
printf("|%-10lf|%-10lf|%-10s|%-10s|\n",next->location.lat,next->location.lng,"Porpoise",next->observer.id);
if (next!=NULL) {
next=next->pointer;
}
}
else {
printf("|%-10lf|%-10lf|%-10s|%-10s|\n",next->location.lat,next->location.lng,"Dolphin",next->observer.id);
if (next!=NULL) {
next=next->pointer;
}
}
}
printf("|==========|==========|==========|==========|\n");
}
void remove_duplicates() {
int i,j;
double distance;
Mammal *next=head2.pointer;
for(i=0;i<list_length2-1;i++) {
Mammal *check=next->pointer;
Duplicate d;
d.mampointer=NULL;
d.number_of=0;
for(j=0;j<(list_length2-i)-1;j++) {
distance=great_circle(next->location, check->location);
if(distance<=0.02 && next->species==check->species) {
Mammal a=*next;
Mammal b=*check;
a.pointer=d.mampointer;
d.mampointer=&a;
b.pointer=d.mampointer;
d.mampointer=&b;
d.number_of++;
d.number_of++;
}
printf("%f\n",distance);
if (check!=NULL) {
check=check->pointer;
}
}
if(d.mampointer!=NULL) {
add_duplicate(create_duplicate(&d));
}
if (next!=NULL) {
next=next->pointer;
}
}
}
void print_list3() {
Duplicate *next=head3.duppointer;
int i,j;
for(i=0;i<list_length3;i++) {
printf("%c %d %f %f\n",next->species,next->number_of,next->location.lat,next->location.lng);
Mammal mam;
mam=*next->mampointer;
for(j=0;j<next->number_of;j++) {
printf(" %f %f %s\n",mam.location.lat,mam.location.lng,mam.observer.id);
if (mam.pointer!=NULL) {
mam=*mam.pointer;
}
}
if (next!=NULL) {
next=next->duppointer;
}
}
}
答案 0 :(得分：1)
第一眼就有很多问题。
这是C，但最好避免使用名称＆＃39; new＆＃39;。标识符位置＆＃39;也是结构名称和变量名称。函数char get_directories（）和Observer * find_observer（）并不总是返回。
有五个malloc（）但没有free（）调用。
我担心这样的函数声明不能保证字符串大小，传递一个简单的指针：
Observer * create_observer ( char id[5], ..
未检查fscanf的返回值。预期6但实际上返回1，因为没有提供适当的格式。也许尝试＆＃34;％2d％2d％2d％2d％2d％2d＆＃34;！
fscanf(file_no1,"%d%d%d%d%d%d",&td.day,&td.month,&td.year,&td.hour,&td.minute,&td.second);
观察者线也有同样的问题。 fscanf应该如何知道字符串和/或double的结尾？试试例如＆＃34;％4s％lf％lf＆＃34;！
while(fscanf(file_no1,"%s%lf%lf",obs->id,&obs->location.lat,&obs->location.lng)==3) {
此时未正确扫描String obsid（删除地址运算符＆amp;）：
while(fscanf(file_no2,"%4s %c %lf%lf",&obsid,&mam->species,&mam->bearing,&mam->range)==4) {
如果找不到obsid，函数find_observer（）将正确返回NULL。在这种情况下不应使用指针，因此请先检查obs2：
Observer* obs2=find_observer(obsid);
mam->observer=*obs2;
您能否提供带有示例输入的代码部分来重现问题并解决问题？我甚至不得不进行逆向工程以获得以下结构进行编译：
struct Loc { double lat; double lng; };
struct TD { int year; int month; int day; int hour; int minute; int second; };
struct Observer { char id[1024]; Loc location; TD timedate; Observer * pointer; };
struct Mammal { char species; double bearing; double range; Observer observer; Mammal * pointer; Loc location; };
struct Duplicate { Mammal * mampointer; int number_of; char species; Loc location; Duplicate * duppointer; };
还缺少great_circle（Loc，Loc）功能。替换为平面距离计算而不是假设的球形：
double great_circle( Loc p0, Loc p1 ) { return pow( ( p0.lat - p1.lat ), 2.0 ) + pow( ( p0.lng - p1.lng ), 2.0 ); }
在没有尝试重复的情况下，在修复上述错误后，它可以正常运行。