小编Edu*_*sta的帖子

我不确定在什么情况下我会想要使用Hash#fetch它Hash#[].是否有一个常见的场景,它会在哪些方面有用？

鉴于相对路径:

PathBuf::from("./cargo_home")

有没有办法获得绝对路径？

==13890== Conditional jump or move depends on uninitialised value(s)
==13890==    at 0x4E7E4F1: vfprintf (vfprintf.c:1629)
==13890==    by 0x4E878D8: printf (printf.c:35)
==13890==    by 0x400729: main (001.c:30)
==13890==  Uninitialised value was created by a stack allocation
==13890==    at 0x400617: main (001.c:11)

引用的行:

int limit = atoi(argv[1]);

我不知道如何解决它.我试过在stackoverflow和谷歌搜索,但我找不到解决方案.

代码(来自修订历史):

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

int main(int argc, char *argv[])
{
    if (argc != 2) {
        printf("You must pass a single integer\n");
        exit(1);
    }

    int limit = atoi(argv[1]); 
    int numbers[limit / 2];
    int count = 0; …

当我运行rspec时,我将其包含在控制台中:

ActiveRecord::SchemaMigration Load (0.1ms)  SELECT "schema_migrations".* FROM     "schema_migrations"
   (0.1ms)  begin transaction
   (0.0ms)  commit transaction
   (0.0ms)  begin transaction
Started GET "/" for 127.0.0.1 at 2014-01-28 11:44:06 -0600
Processing by HomeController#index as HTML
Rendered home/index.html.haml within layouts/application (28.1ms)
Completed 200 OK in 54ms (Views: 52.0ms | ActiveRecord: 0.0ms)
   (0.1ms)  rollback transaction

这是我的spec_helper.rb:

ENV["RAILS_ENV"] ||= 'test'
require File.expand_path("../../config/environment", __FILE__)
require 'rspec/rails'
require 'rspec/autorun'
require 'capybara/rails'
require 'capybara/rspec'

Dir[Rails.root.join("spec/support/**/*.rb")].each { |f| require f }

ActiveRecord::Migration.check_pending! if defined?(ActiveRecord::Migration)

RSpec.configure do |config|
  config.fixture_path = "#{::Rails.root}/spec/fixtures"
  config.use_transactional_fixtures …

这是有问题的代码:

long number = atol(argv[1]);
long prime_limit = number / 2;
int * primes = malloc(sizeof(int) * prime_limit);
long i;
for (i = 2; i <= prime_limit; i++) {
    primes[i] = 1; # This is line 16
}

以下是错误:

==9318== Invalid write of size 4
==9318==    at 0x40065B: main (003.c:16)
==9318==  Address 0x8 is not stack'd, malloc'd or (recently) free'd
==9318== 
==9318== 
==9318== Process terminating with default action of signal 11 (SIGSEGV)
==9318==  Access not within mapped region at address …