c - How to store a character string into a character pointer declared in a structure

Question

This is my code:

 #include<stdio.h>



    struct p{

           char* d;
           };

    typedef struct p* pt;

    int main(){
        pt opt;
        opt=(pt)malloc(sizeof(struct p));

        scanf("%s",(opt->d));


        printf("%s",opt->d);



        getch();

        return 0;

        }

Everytime I run it , it accepts and prints the string fine but an error occur. On debugging it tells that there is a segmentation fault but doesn't points to where it is? What is going wrong , It's seems to be fairly correct.

Answer 1

You used malloc to allocate space for your structure, but not for the string you want to read in. You need to do that too. Here's an example paraphrased from your question:

 pt opt = malloc(sizeof(struct p));
 opt->d = malloc(MAX_STRING_LENGTH);