"%4s%-4.2f","身高:",height中,的意思
时间: 2024-06-16 18:01:50 浏览: 119
在C/C++编程语言中,格式化字符串`"%4s%-4.2f"`是一个用于输出数据到控制台或者文件的格式说明符。这里每个部分代表:
- `%4s`: 这是一个格式说明符,其中`s`表示字符串类型,前边的`4`是宽度(或最小宽度),意味着输出的字符串将至少占据4个字符的位置。如果字符串本身长度不足4个字符,前面会用空格填充,以保持总宽度。
- `%-`: 前缀符号`-`表示左对齐,这样如果字符串内容比指定宽度短,空格将放在右侧而不是左侧。
- `4.2f`: 这是用来表示浮点数的格式,`.2f`表示最多保留两位小数。`4`同样是指定宽度,对于浮点数,这包括了整数部分和小数点后的位数。
整个表达式`"身高:"`是一个字符串,用来标识后面将要显示的数据类型,即身高。当用这个格式字符串输出`height`变量的值时,首先会显示"身高:",然后是对应数值,按照格式对齐并保留两位小数。
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;
}
```
#loader { position: absolute; left: 50%; top: 10%; z-index: 1; /*width: 20px;*/ /*height: 20px;*/ margin: -25px 0 0 -25px; border: 6px solid #f3f3f3; border-radius: 50%; border-top: 6px solid #00A76F; border-bottom: 6px solid #00A76F; width: 50px; height: 50px; -webkit-animation: spin 2s linear infinite; animation: spin 2s linear infinite; } @-webkit-keyframes spin { 0% { -webkit-transform: rotate(0deg); } 100% { -webkit-transform: rotate(360deg); } } @keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }
这段 CSS 代码定义了一个名为 `loader` 的元素的样式,该元素会呈现旋转的圆形加载动画。具体解释如下:
1. `position: absolute;`:使元素的定位方式为绝对定位,相对于最近的非 static 定位的祖先元素进行定位。
2. `left: 50%;` 和 `top: 10%;`:将元素的位置水平居中并垂直偏离顶部 10% 的位置。
3. `z-index: 1;`:设置元素的堆叠顺序为 1。
4. `border: 6px solid #f3f3f3;`:定义元素的边框,宽度为 6px,颜色为 #f3f3f3。
5. `border-radius: 50%;`:将元素的边框设置为圆形。
6. `border-top: 6px solid #00A76F;` 和 `border-bottom: 6px solid #00A76F;`:定义元素的顶部和底部边框的颜色为 #00A76F。
7. `width: 50px;` 和 `height: 50px;`:定义元素的宽度和高度均为 50px。
8. `-webkit-animation: spin 2s linear infinite;` 和 `animation: spin 2s linear infinite;`:定义元素的动画,持续时间为 2s,动画函数为 linear,循环播放。其中 `-webkit-animation` 用于兼容 Safari 和 Chrome 浏览器。
9. `@-webkit-keyframes spin` 和 `@keyframes spin`:定义名为 `spin` 的动画,从 0% 到 100% 的过程中将元素旋转 360 度,使其呈现加载动画。
综上所述,这段 CSS 代码通过定义元素的样式和动画,实现了一个简单的圆形加载动画效果。