这是我正在尝试实施的详细程序:一位博物学家准备去探索亚马逊丛林,并且需要一个计算机程序来记录有关所有发现的新物种的信息。对于每个新物种,都必须存储名称(最多128个字符),大小(实数)和动物类型。哺乳动物,昆虫,鸟类或鱼类)。这是示例运行的样子(键盘输入以斜体显示)...
> NewSpecies
Enter animal information ("exit" to exit)
What is the name : bloatfish
What is the size : 12.47
What is the type : fish
Enter animal information ("exit" to exit)
What is the name : stingybeasty
What is the size : 0.13
What is the type : insect
Enter animal information ("exit" to exit)
What is the name : toothfulsloth
What is the size : 33.33
What is the type : mammal
Enter animal information ("exit" to exit)
What is the name : exit
The following new species were found:
bloatfish has size 12.47 and is a fish
stingybeasty has size 0.13 and is a insect
toothfulsloth has size 33.33 and is a mammal
You must ...
Implement the program in C.
必须使用结构数组,以便可以将每个新物种记录在数组的元素中。动物的类型表示为枚举类型,表示哺乳动物,昆虫,鸟类或鱼类中的一种。事先未知会发现多少个新的物种,因此程序必须为大小为1的初始数组malloc,并使用加倍的realloc技术按需获取更多内存。您必须始终检查malloc的返回值,就像在Malloc包装函数中一样(或仅使用Malloc:-)。
我的尝试:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define MAX_CHAR 128
#define LENGTH(A) (sizeof(A)/sizeof(A[0]))
typedef char String[MAX_CHAR];
typedef enum {mammal, insect, bird, fish, error} AnimalType;
typedef struct{
String name;
double size;
AnimalType type;
} Animal;
void * Malloc(size_t Size) {
void * Memory;
if ((Memory = malloc(Size)) == NULL) {
perror("Cannot malloc");
exit(EXIT_FAILURE);
} else {
return(Memory);
}
}
AnimalType CheckAnimalType(String type) {
if (!strcmp(type,"mammal")) {
return (mammal);
}
if (!strcmp(type,"insect")) {
return (insect);
}
if (!strcmp(type,"bird")) {
return (bird);
}
if (!strcmp(type,"fish")) {
return (fish);
}
return (error);
}
char *PrintAnimalType(AnimalType type){
switch(type){
case mammal: return "mammal"; break;
case insect: return "insect"; break;
case bird: return "bird"; break;
case fish: return "fish"; break;
case error: return "error";
}
return "error";
}
void printData(Animal *animal, int size) {
printf("The following species were found:\n");
for(int i = 0; i < size-1; i++)
printf("%s has size %.2lf and is a %s\n", animal[i].name, animal[i].size, PrintAnimalType(animal[i].type));
}
void MainMenu(Animal *animal, int *size){
for(;;){
Animal newAnimal;
String animalName;
double animalSize;
String animalType;
printf("Enter animal information (\"exit\" to exit)\n");
printf("What is the name : ");
scanf("%s", animalName);
if(!strcmp(animalName, "exit")) break;
strcpy(newAnimal.name, animalName);
printf("What is the size : ");
scanf("%lf", &animalSize);
if(newAnimal.size == 0) break;
newAnimal.size = animalSize;
printf("What is the type : ");
scanf("%s", animalType);
newAnimal.type = CheckAnimalType(animalType);
if((animal = realloc(animal, sizeof(newAnimal)*((*size)+1))) == NULL) {
printf("MEMORY ERROR: problem reallocating array\n");
return;
}
animal[(*size)-1] = newAnimal;
(*size)++;
}
printData(animal, *size);
}
int main(void) {
int size = 1;
Animal *animal = Malloc(sizeof(Animal));
MainMenu(animal, &size);
free(animal);
return 0;
}
我正在尝试用C实现上述功能,但执行后直接收到此错误:
在MainMenu
中,您在realloc
上呼叫animal
。这可能会调整现有缓冲区的大小,但通常会分配一个新的on,从而更改指针的值。新指针存储在本地animal
变量中,而不存储在main
中。
返回到main
时,调用free(animal)
,这将尝试释放通过调用realloc
已经释放的原始动物缓冲区。
[您将想要将修改后的缓冲区指针作为返回值传递给调用者,或者通过将指针传递给原始变量(Animal **
)。