Question

I’m having a segmentation fault when I want to save a string in a dynamic array.

I have a program that does this:

User insert char “s”
The program enters a loop and save strings in an array (name: cod).
When user inserts char “t”, it stops

After that I save that array in the first position of a new dynamic array (name: vec).

Then if user insert char “s” again
The program enters a loop and save strings in an array.
When user inserts char “t”, it stops

After that I save that array in the second position of a new dynamic array.

and so one.

This is my code:

int main(){

char Cod[30][11];
char tmp[11];
char ***vec;
int i = 0;


strcpy (tmp, "p");

vec = (char *** ) malloc (sizeof ( char *) );
vec[0] = (char ** ) malloc (sizeof ( char *) * 30);


do {

    scanf("%s", tmp);

    while( (strcmp (tmp, "p")) != 0){

        strcpy ( Cod[i] , tmp ); 

        scanf("%s", tmp);

        i++;
    }

    vec = (char ***) realloc (vec, sizeof ( char *) * (i + 1));
    vec[i + 1] = (char ** ) realloc (vec[i + 1], sizeof ( char *) * (30));
    vec[i-1] = (char **) Cod;
    scanf("%s", tmp);

}

while((strcmp (tmp, "s")) == 0);

    printf("%s", vec[0][0]);

return 0;

}

This is the part of the code that work’s:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>


int main(){

    char Cod[30][11];
    char tmp[11];
    int i = 0;


    strcpy (tmp, "p");


    do {

        scanf("%s", tmp);

        while( (strcmp (tmp, "p")) != 0){

            strcpy ( Cod[i] , tmp ); 

            scanf("%s", tmp);

            i++;
        }

        scanf("%s", tmp);

    }

    while((strcmp (tmp, "s")) == 0);

        printf("%s", Cod[0]);

return 0;

}

Answer 1

Since it is a homework I tried to rewrite your code in something that should work…

char Cod[30][11];
char tmp[11];
char ***vec;
int i = 0;


strcpy (tmp, "p");
vec = (char***)malloc(sizeof(char *));
vec[0] = (char**)malloc(sizeof(Cod));


do {
    scanf("%s", tmp);        
    int j = 0;
    while(strcmp(tmp, "p")) {
        strcpy(Cod[j], tmp);
        scanf("%s", tmp);
        j++;
    }
    vec = (char ***)realloc(vec, sizeof(char *) * (i+1));
    vec[i] = (char **)malloc(sizeof(Cod));
    memcpy(vec[i], Cod, sizeof(Cod));//you need to copy results since next time the Cod will be rewritten
    scanf("%s", tmp);
    i++;
} while((strcmp(tmp, "s")) == 0);