Analyze this source

// Analyze this source code and specify the flaw of this source code?

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

int main(int argc, char **argv){
    char command[256];
    if (argc != 2){
        printf("Eroror: Please enter a program to time!\n");
        return -1;
    }
    memset(&command, 0, sizeof(command));
    strcat(command, "time ./");
    strcat(command, "argv[1]");
    system(command);
    return 0;
}