7 14 D:\mycode\C++\题\语法.cpp [Warning] multi-character character constant [-Wmultichar]
时间: 2023-07-21 10:08:43 浏览: 73
这个警告是由于你在代码中使用了多字符字符常量。在C++中,字符常量应该只包含一个字符,如 'a' 或 '1'。如果你使用了多个字符,编译器会给出这个警告。在你的代码中,你可能使用了一个以上的字符来定义一个字符常量。
例如,如果你写了类似这样的代码:
```cpp
char c = 'ab';
```
编译器会给出警告,因为 'ab' 包含了两个字符。你可以将它改为单个字符的常量,或者使用字符串来表示多个字符。
如果你想表示一个字符串而不是字符常量,你可以使用双引号来包围它,如:
```cpp
char* str = "ab";
```
这样就不会出现多字符字符常量的警告了。记住,在C++中,单引号用于字符常量,双引号用于字符串常量。
相关问题
优化下面代码.bg { width: 100%; height: 100vh; background-image: url('../../assets/img/info-bg.png'); background-size: 100% 100%; background-repeat: no-repeat; position: relative; font-family: AlibabaPuHuiTiR; .goBack { position: absolute; top: 34px; right: 65px; cursor: pointer; color: #ffffff; width: 181px; padding: 15px 10px; background: rgba(24, 31, 30, 0.52); border: 1px solid #4a524e; border-radius: 5px; font-size: 18px; font-family: AlibabaPuHuiTiR; z-index: 111; display: flex; flex-direction: row; justify-content: space-between; align-items: center; } .home-left { position: absolute; top: 18%; left: 40px; width: 41%; height: 76%; font-size: 24px; color: #ffffff; } .unit { font-size: 24px; color: #636363; } .home-left-title { font-size: 24px; color: #ffffff; line-height: 36px; } .home-right { position: absolute; top: 18%; right: 88px; width: 46%; height: 78%; } .model { display: flex; justify-content: center; align-items: center; height: 90%; } #threeContained { width: 100%; height: 100%; } .model-qk-img { width: 82%; height: 90%; background-image: url('../../assets/img/howo.png'); background-size: 100% 100%; background-repeat: no-repeat; } .model-zk-img { width: 56%; height: 90%; background-image: url('../../assets/img/heavyT.png'); background-size: 100% 100%; background-repeat: no-repeat; } .model-gj-img { width: 82%; height: 90%; background-image: url('../../assets/img/transit.png'); background-size: 100% 100%; background-repeat: no-repeat; } .car-online { margin-bottom: 50px; } } .day-data { display: flex; flex-direction: row; justify-content: space-between; align-items: center; height: 29%; margin-left: 30px; } .day-val { width: 40%; } .prefix { display: inline-block; width: 6px; height: 14px; background: #ffffff; margin-right: 20px; } .zh-title { margin-left: 30px; padding-top: 30px; font-size: 30px; font-weight: 700; text-align: left; color: #ffffff; line-height: 32px; letter-spacing: 0.3px; font-family: AlibabaPuHuiTiB; } .en-title { margin-left: 30px; font-size: 14px; font-weight: 400; text-align: left; color: #ffffff; line-height: 32px; letter-spacing: -0.91px; font-family: AlibabaPuHuiTiR; }
Here are some suggestions to optimize the code:
1. Use shorthand properties whenever possible. For example, instead of writing `background-size: 100% 100%;`, you can write `background-size: cover;`.
2. Consolidate similar styles into classes, instead of repeating them for every element. For example, you can create a class for the font family and apply it to all elements that use that font.
3. Remove unnecessary styles that are not being used or overwritten by other styles.
4. Use more specific selectors to target elements, instead of relying on the order of elements in the HTML. This will make the code more robust and easier to maintain.
5. Consider using a CSS preprocessor like Sass or Less, which can help you write cleaner and more organized code.
Here's an example of how the code could be optimized:
```
.bg {
width: 100%;
height: 100vh;
background: url('../../assets/img/info-bg.png') no-repeat center center / cover;
position: relative;
font-family: AlibabaPuHuiTiR;
}
.goBack {
position: absolute;
top: 34px;
right: 65px;
cursor: pointer;
color: #fff;
width: 181px;
padding: 15px 10px;
background: rgba(24, 31, 30, 0.52);
border: 1px solid #4a524e;
border-radius: 5px;
font-size: 18px;
font-family: AlibabaPuHuiTiR;
z-index: 111;
display: flex;
flex-direction: row;
justify-content: space-between;
align-items: center;
}
.home-left {
position: absolute;
top: 18%;
left: 40px;
width: 41%;
height: 76%;
font-size: 24px;
color: #fff;
}
.unit {
font-size: 24px;
color: #636363;
}
.home-left-title {
font-size: 24px;
color: #fff;
line-height: 36px;
}
.home-right {
position: absolute;
top: 18%;
right: 88px;
width: 46%;
height: 78%;
}
.model {
display: flex;
justify-content: center;
align-items: center;
height: 90%;
}
#threeContained {
width: 100%;
height: 100%;
}
.model-qk-img {
width: 82%;
height: 90%;
background: url('../../assets/img/howo.png') no-repeat center center / cover;
}
.model-zk-img {
width: 56%;
height: 90%;
background: url('../../assets/img/heavyT.png') no-repeat center center / cover;
}
.model-gj-img {
width: 82%;
height: 90%;
background: url('../../assets/img/transit.png') no-repeat center center / cover;
}
.car-online {
margin-bottom: 50px;
}
.day-data {
display: flex;
justify-content: space-between;
align-items: center;
height: 29%;
margin-left: 30px;
}
.day-val {
width: 40%;
}
.prefix {
display: inline-block;
width: 6px;
height: 14px;
background: #fff;
margin-right: 20px;
}
.zh-title {
margin-left: 30px;
padding-top: 30px;
font-size: 30px;
font-weight: 700;
text-align: left;
color: #fff;
line-height: 32px;
letter-spacing: 0.3px;
font-family: AlibabaPuHuiTiB;
}
.en-title {
margin-left: 30px;
font-size: 14px;
font-weight: 400;
text-align: left;
color: #fff;
line-height: 32px;
letter-spacing: -0.91px;
font-family: AlibabaPuHuiTiR;
}
.font-alibaba {
font-family: AlibabaPuHuiTiR;
}
.font-alibaba-bold {
font-family: AlibabaPuHuiTiB;
}
```
请根据如下描述写一段python代码 1、文件test.txt的内容为: https://pixcelcell-glamme-app.s3.us-east-1.amazonaws.com/ai-engine/avatar/202307/1690195044-20268753802.jpg https://pixcelcell-glamme-app.s3.us-east-1.amazonaws.com/ai-engine/avatar/202307/1690195069-92997461737.jpg https://pixcelcell-glamme-app.s3.us-east-1.amazonaws.com/ai-engine/avatar/202307/1690195088-1889167480.jpg 2、打开test文件并把图片下载到本地D:picture文件里
你可以使用 Python 的 `requests` 库来下载图片,并使用文件操作来读取和写入文件。以下是一段代码,根据你的描述实现了这个功能:
```python
import requests
# 文件路径
file_path = "test.txt"
# 图片保存目录
save_directory = "D:/picture/"
# 打开文件并逐行读取图片链接
with open(file_path, 'r') as file:
for line in file:
# 去除行尾的换行符
image_url = line.strip()
# 发送请求并下载图片
response = requests.get(image_url)
if response.status_code == 200:
# 从URL中提取文件名
filename = image_url.split("/")[-1]
# 拼接保存路径
save_path = save_directory + filename
# 写入文件
with open(save_path, 'wb') as image_file:
image_file.write(response.content)
print(f"图片 {filename} 下载成功")
else:
print(f"无法下载图片 {image_url}")
```
在上述代码中,我们先定义了 `file_path` 变量来表示包含图片链接的文本文件路径,以及 `save_directory` 变量来表示图片保存的目录。
然后,我们使用 `with open(file_path, 'r') as file` 打开文件,逐行读取图片链接。对于每个链接,我们发送 GET 请求获取图片内容,并将其保存到本地。我们使用 `requests.get()` 方法发送请求,如果响应状态码为 200,则表示请求成功。我们从链接中提取文件名,并将其与保存目录拼接为完整的保存路径。然后,我们使用 `open(save_path, 'wb')` 打开二进制文件并将响应内容写入文件中。
最后,我们通过 `print()` 函数打印出下载成功或失败的消息。
请确保指定的文件路径和保存目录是正确的,并具有相应的权限。希望这段代码能满足你的需求!
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