动态内存分配的补充 realloc和calloc函数

Posted 2020-11-26 panghushalu

malloc calloc realloc 都是<stdilb.h>头文件的函数
函数原型：
void malloc(unsigned int num_bytes)
void calloc(size_t n, size_t size)
void realloc(void *ptr, size_t new_Size)

先说malloc和calloc区别
malloc分配的空间里都是垃圾值，而calloc里全是0
但是malloc的效率比calloc的高

# include <stdio.h>
# include <malloc.h>
int main()
{
    int* p;
    int* pp;
    p = (int*)malloc(10 * sizeof(int));
    pp = (int*)calloc(10 ,sizeof(int));
    printf("malloc的存储空间：
");
    for (int i = 0; i < 10; i++)
    {
        printf("%d ", *(p+i));
    }
    printf("
");
    printf("calloc的存储空间：
");
    for (int i = 0; i < 10; i++)
    {
        printf("%d ", *(pp+i));
    }
    printf("
");
    return 0;
}