Getting string with C function

Question

I need to get strings dynamically but as I need to get more than one string, I need to use functions. So far I wrote this (I put //**** at places i think might be wrong)

char* getstring(char *str);

int main() {

    char *str;
    strcpy(str,getstring(str));//*****
    printf("\nString: %s", str);
    return 0;
}

char* getstring(char str[]){//*****
    //this part is copy paste from my teacher lol
    char c;
    int i = 0, j = 1;
    str = (char*) malloc (sizeof(char));
    printf("Input String:\n ");
    while (c != '\n') {//as long as c is not "enter" copy to str
        c = getc(stdin);
        str = (char*)realloc(str, j * sizeof(char));
        str[i] = c;
        i++;
        j++;
    }
    str[i] = '\0';//null at the end
    printf("\nString: %s", str);
    return str;//******
}

printf in the function is working but not back in main function. I tried returning void, getting rid of *s or adding, making another str2 and tring to strcpy there or not using strcpy at all. Nothing seems to working. Am I misssing something? Or maybe this is not possible at all //Thank you so much for your answers

Answer 1

Getting the string part can be taken from this answer. Only put a \n as input to the getline funtion.

char * p = getline('\n');

Three things :- don't cast malloc, check if malloc/realloc is successful and sizeof is not a function.

Answer 2

The problem is not with the function that you are using, but with the way you try copying its result into an uninitialized pointer.

Good news is that you don't have to copy - your function already allocates a string in dynamic memory, so you can copy the pointer directly:

char *str = getstring(str);

This should fix the crash. A few points to consider to make your function better:

• main needs to free(str) when it is done in order to avoid memory leak
• Store realloc result in a temporary pointer, and do a NULL check to handle out-of-memory situations properly