CODEWITHSUNDEEP
cpointersstructcrash
orion
orion

Reputation: 15

scanf of struct makes program crash

this is the code. the function "leggi" is supposed to read the value of c[i].a but when I type the first number in the console the program crashes. It's probably a pointers issue but i can't figure it out

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

typedef struct cane{
    int a;
}cane;

void leggi(cane *c[20]){
    int i;
    for(i=0;i<5;i++)
        scanf("%d", &c[i]->a );
}

int main(){
    int i;
    cane c[20];

    leggi(&c);

    for(i=0;i<5;i++)
        printf("%d",c[i].a);

    return 0;
}

Upvotes: 0

Views: 145

Answers (2)

eerorika
eerorika

Reputation: 238341

The type of &c is cane (*)[20] i.e. a pointer to an array. You've declared the argument of the function to be cane *[20] which is (as a function argument) a cane** which is a pointer to a pointer.

You may have intended to pass a pointer to an element of the array instead:

void leggi(cane *c)
    // ...
    scanf("%d", &c[i].a );

//
leggi(c);

Or possibly you really intended to pass a pointer to the array instead:

void leggi(cane (*c)[20])
    scanf("%d", &(*c)[i].a )

//
leggi(&c);

Upvotes: 1

Osiris
Osiris

Reputation: 2813

You pass the wrong type to the function.

If you want to pass an array to a function the array name decays to a pointer to its first element, therefore the argument is only a pointer to the type:

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

typedef struct cane{
    int a;
}cane;

void leggi(cane *c){
    int i;
    for(i=0;i<5;i++)
        scanf("%d", &(c[i].a) );
}

int main(){
    int i;
    cane c[20];

    leggi(c);

    for(i=0;i<5;i++)
        printf("%d",c[i].a);

    return 0;
}

Upvotes: 3

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