英文:
Seg fault when using scanf to define the size
问题
I have a strange issue with my code:
我在我的代码中遇到了一个奇怪的问题：
I have a function generating a dynamic array of struct and only takes an int size as parameter.
我有一个函数生成一个结构体的动态数组，并只接受一个整数大小作为参数。
It's work well until i try to add just a scanf("d";&size); to choose the size of my array, can't understand why i get a seg fault.
一切都很正常，直到我尝试添加scanf("d";&size);来选择数组的大小，我不明白为什么会导致段错误。
Note : There is no issue with compilation if i remove the line containing scanf
注意：如果我删除包含scanf的行，编译就没有问题
pokemon_t * createPkmDatabase( int taille){printf("taille %d",taille);pokemon_t *tableau=malloc(sizeof(pokemon_t)*taille);......}
int main(){/*"taille" means size in French */int taille=5;printf("Saisir taille : ");scanf("%d",&taille); /* <-- BREAKS EVERYTHING */printf("valeur de taille : %d\n ",taille);pokemon_t *database=createPkmDatabase(taille);}
I don't get why changing the value of "taille" with a simple scanf change anything the value.
我不明白为什么用一个简单的scanf更改"taille"的值会改变任何值。
It doesn't even seem to enter the function because it doesn't even print the value of the size.
它甚至似乎没有进入函数，因为它甚至不打印大小的值。
英文:
I have a strange issue with my code :
I have a function generating a dynamic array of struct and only takes an int size as parameter.
It's work well until i try to add just a scanf("d";&size); to choose the size of my array, can't understand why i get a seg fault.
Note : There is no issue with compilation if i remove the line containing scanf
pokemon_t * createPkmDatabase( int taille){printf("taille %d",taille);pokemon_t *tableau=malloc(sizeof(pokemon_t)*taille);......}
int main(){/*"taille" means size in french */int taille=5;printf("Saisir taille : ");scanf("%d",&taille); /* <-- BREAKS EVERYTHING */printf("valeur de taille : %d\n ",taille);pokemon_t *database=createPkmDatabase(taille);}
I don't get why changing the value of "taille" with a simple scanf change anything the value.
It doesn't even seems to enter in the function bc it doesn't even print the value of the size
答案1
得分: 1
在展示的代码中没有错误。一些建议：1. 对于大小，请使用正确的类型（`size_t`）2. 始终检查 `scanf` 和 `malloc` 的结果typedef struct {int x, y, z;} pokemon_t;pokemon_t *createPkmDatabase(size_t taille){printf("taille %d", taille);pokemon_t *tableau = malloc(sizeof(*tableau) * taille);return tableau;}int main(){/* "taille" 在法语中意味着大小 */size_t taille;printf("Saisir taille : ");if(scanf("%zu", &taille) == 1){printf("valeur de taille : %zu\n ", taille);pokemon_t *database = createPkmDatabase(taille);if(database){printf("\nAllocation OK\n");}else{printf("\nAllocation FAILED\n");}free(database);}}
英文:
There are no errors in the code shown.
Some remarks:
- Use the correct type for sizes (
size_t) - Always check the result of
scanfandmalloc
typedef struct {int x,y,z;}pokemon_t;pokemon_t * createPkmDatabase(size_t taille){printf("taille %d",taille);pokemon_t *tableau=malloc(sizeof(*tableau)*taille);return tableau;}int main(){/*"taille" means size in french */size_t taille;printf("Saisir taille : ");if(scanf("%zu",&taille) == 1){printf("valeur de taille : %zu\n ",taille);pokemon_t *database=createPkmDatabase(taille);if(database){printf("\nAllocation OK\n");}else{printf("\nAllocation FAILED\n");}free(database);}}
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