为什么结果显示分段错误？

Question

程序要求用户输入两个值，在指针中存储值后，打印分段错误并终止。为什么？

// c program to add two numbers using pointers

#include <stdio.h>

int main()
{
    int *ptr1, *ptr2, sum;

    printf ("Enter the two numbers:\n");
    scanf ("%d %d", ptr1, ptr2);

    sum = *ptr1 + *ptr2;
    printf("The result is %d", sum);
    return 0;

Answer 1

这是因为你没有为ptr1和ptr2分配内存。

#include <stdio.h>

int main()
{
    int *ptr1=0, *ptr2=0, sum=0;

    ptr1= malloc(sizeof(int));
    if(0 == ptr1) //Check if mem allocation is successful.
    {
        printf("Failed to allocate memory for ptr1\n");
        return 0;
    }

    ptr2= malloc(sizeof(int));
    if(0 == ptr2) //Check if mem allocation is successful.
    {
        printf("Failed to allocate memory for ptr2\n");
        free(ptr1); //Free ptr1 memory
        return 0;
    }

    printf ("Enter the two numbers:\n");
    scanf ("%d %d", ptr1, ptr2);

    sum = *ptr1 + *ptr2;
    printf("The result is %d", sum);

    free(ptr2); //Free ptr2 memory
    free(ptr1); //Free ptr1 memory
    return 0;
}