Thread: help with malloc

I'm trying to write a program that combines all command line arguments into one string.

Code:

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

int main(int argc, char *argv[]) {
    int i;
    char *vector;
    size_t length;
    
    i = 0;
    while (i < argc) {
        length = length + strlen(argv[i]) + 1;
        i++;
    }
    
    vector = malloc(sizeof(char) * length);
    assert(vertor != NULL);

    strcpy(vector, argv[0]);
    i = 1;
    while (i < argc) {
        strcat(vector, argv[i]);
        i++;
    }

    printf("%s\n", vector);
    
    free(vector);
    
    return EXIT_SUCCESS;
}

My code compiles and run fine on iMac with gcc, but when I run it on my school system it gives me error message saying "uninitialized variable accessed".

Also, what is the difference between (char *)malloc(sizeof(char) * length) and just malloc(sizeof(char) * length)? We were taught the previous in school, but everyone uses the second one online.

Thank you so much!

On line 13 you appear to be using length before you assign an initial value.

Jim

Originally Posted by jimblumberg

On line 13 you appear to be using length before you assign an initial value.

Jim

THANK YOU IT WORKS NOW!!! I thought I was using malloc wrong