c语言输入alpha输出sin cos怎么写
时间: 2024-09-26 09:07:58 浏览: 26
在C语言中,你可以使用`math.h`库中的`sinf()`和`cosf()`函数来计算正弦和余弦值。但是,用户直接输入字母`alpha`然后转换成数学运算并不常见,因为C语言的标准输入处理通常用于接收数值输入。如果你想让用户输入角度(如弧度制下的`alpha`),你可以先将输入转换为合适的数据类型(例如`float`),再进行计算。下面是一个简单的示例:
```c
#include <stdio.h>
#include <math.h>
int main() {
float alpha;
printf("请输入一个角度(弧度):");
scanf("%f", &alpha); // 用户输入
float sin_alpha = sinf(alpha);
float cos_alpha = cosf(alpha);
printf("正弦值(sin): %.4f\n", sin_alpha);
printf("余弦值(cos): %.4f\n", cos_alpha);
return 0;
}
```
在这个程序中,我们首先提示用户输入角度,然后使用`scanf()`读取并存储这个值。接着,我们分别计算并打印出对应的正弦和余弦值。
相关问题
如何用C语言写巴特沃斯高通滤波器,要求输入输出均为长整型
巴特沃斯高通滤波器是一种数字滤波器,用于滤除低频信号并保留高频信号。下面是一个用C语言实现巴特沃斯高通滤波器的示例代码,输入输出均为长整型:
```c
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define M_PI 3.14159265358979323846
long b[3]; // 分子系数
long a[3]; // 分母系数
long x[3]; // 输入信号
long y[3]; // 输出信号
void butterworth_highpass_filter(long fc, int fs, double Q)
{
double w0 = 2 * M_PI * fc / fs;
double alpha = sin(w0) / (2 * Q);
double cosw0 = cos(w0);
double alpha2 = alpha * alpha;
b[0] = (long)((1 - cosw0) / 2 * pow(2, 30));
b[1] = (long)((1 - cosw0) * pow(2, 30));
b[2] = (long)((1 - cosw0) / 2 * pow(2, 30));
a[0] = pow(2, 30) + (long)(alpha * pow(2, 30));
a[1] = (long)(-2 * cosw0 * pow(2, 30));
a[2] = pow(2, 30) - (long)(alpha * pow(2, 30));
double gain = 1 / (double)a[0];
b[0] = (long)(b[0] * gain);
b[1] = (long)(b[1] * gain);
b[2] = (long)(b[2] * gain);
a[1] = (long)(-a[1]);
a[2] = (long)(-a[2]);
x[0] = x[1] = x[2] = 0;
y[0] = y[1] = y[2] = 0;
}
long butterworth_highpass_filter_apply(long input)
{
x[2] = x[1];
x[1] = x[0];
x[0] = input;
y[2] = y[1];
y[1] = y[0];
y[0] = (long)((b[0] * x[0] + b[1] * x[1] + b[2] * x[2] - a[1] * y[1] - a[2] * y[2]) / (double)a[0]);
return y[0];
}
int main()
{
long fc = 1000; // 截止频率为1kHz
int fs = 8000; // 采样率为8kHz
double Q = 0.707; // 质因数Q为0.707
butterworth_highpass_filter(fc, fs, Q);
// 生成测试信号,1s的8000Hz正弦波
int num_samples = 8000;
long test_signal[num_samples];
for (int i = 0; i < num_samples; i++) {
test_signal[i] = (long)(sin(2 * M_PI * i * 1000 / fs) * pow(2, 30));
}
// 对测试信号进行滤波
long filtered_signal[num_samples];
for (int i = 0; i < num_samples; i++) {
filtered_signal[i] = butterworth_highpass_filter_apply(test_signal[i]);
}
// 将结果输出到文件
FILE *fp = fopen("filtered_signal.txt", "w");
if (fp == NULL) {
printf("Failed to open file\n");
return 1;
}
for (int i = 0; i < num_samples; i++) {
fprintf(fp, "%ld\n", filtered_signal[i]);
}
fclose(fp);
return 0;
}
```
在这个示例中,我们首先定义了一个 `butterworth_highpass_filter` 函数,用于计算巴特沃斯高通滤波器的分子和分母系数。然后,我们定义了一个 `butterworth_highpass_filter_apply` 函数,用于对输入信号进行滤波。在 `main` 函数中,我们首先生成了一个1秒钟的正弦波作为测试信号,然后对其进行滤波,并将结果输出到文件中。
需要注意的是,在这个示例中,我们将输入信号和输出信号都乘以了 $2^{30}$,以避免在计算过程中出现浮点运算误差。在使用时,需要根据具体的需求进行修改。
用c语言输入一个爱心代码
```
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<style>
* {
padding: 0;
margin: 0;
}
html,
body {
height: 100%;
padding: 0;
margin: 0;
background: #000;
}
canvas {
position: absolute;
width: 100%;
height: 100%;
}
.aa {
position: fixed;
left: 50%;
bottom: 10px;
color: #ccc;
}
</style>
<body>
<canvas id="pinkboard"></canvas>
<script>
/*
* Settings
*/
var settings = {
particles: {
length: 500, // maximum amount of particles
duration: 2, // particle duration in sec
velocity: 100, // particle velocity in pixels/sec
effect: -0.75, // play with this for a nice effect
size: 30 // particle size in pixels
}
};
/*
* RequestAnimationFrame polyfill by Erik M?ller
*/
(function () {
var b = 0;
var c = ["ms", "moz", "webkit", "o"];
for (var a = 0; a < c.length && !window.requestAnimationFrame; ++a) {
window.requestAnimationFrame = window[c[a] + "RequestAnimationFrame"];
window.cancelAnimationFrame =
window[c[a] + "CancelAnimationFrame"] ||
window[c[a] + "CancelRequestAnimationFrame"];
}
if (!window.requestAnimationFrame) {
window.requestAnimationFrame = function (h, e) {
var d = new Date().getTime();
var f = Math.max(0, 16 - (d - b));
var g = window.setTimeout(function () {
h(d + f);
}, f);
b = d + f;
return g;
};
}
if (!window.cancelAnimationFrame) {
window.cancelAnimationFrame = function (d) {
clearTimeout(d);
};
}
})();
/*
* Point class
*/
var Point = (function () {
function Point(x, y) {
this.x = typeof x !== "undefined" ? x : 0;
this.y = typeof y !== "undefined" ? y : 0;
}
Point.prototype.clone = function () {
return new Point(this.x, this.y);
};
Point.prototype.length = function (length) {
if (typeof length == "undefined")
return Math.sqrt(this.x * this.x + this.y * this.y);
this.normalize();
this.x *= length;
this.y *= length;
return this;
};
Point.prototype.normalize = function () {
var length = this.length();
this.x /= length;
this.y /= length;
return this;
};
return Point;
})();
/*
* Particle class
*/
var Particle = (function () {
function Particle() {
this.position = new Point();
this.velocity = new Point();
this.acceleration = new Point();
this.age = 0;
}
Particle.prototype.initialize = function (x, y, dx, dy) {
this.position.x = x;
this.position.y = y;
this.velocity.x = dx;
this.velocity.y = dy;
this.acceleration.x = dx * settings.particles.effect;
this.acceleration.y = dy * settings.particles.effect;
this.age = 0;
};
Particle.prototype.update = function (deltaTime) {
this.position.x += this.velocity.x * deltaTime;
this.position.y += this.velocity.y * deltaTime;
this.velocity.x += this.acceleration.x * deltaTime;
this.velocity.y += this.acceleration.y * deltaTime;
this.age += deltaTime;
};
Particle.prototype.draw = function (context, image) {
function ease(t) {
return --t * t * t + 1;
}
var size = image.width * ease(this.age / settings.particles.duration);
context.globalAlpha = 1 - this.age / settings.particles.duration;
context.drawImage(
image,
this.position.x - size / 2,
this.position.y - size / 2,
size,
size
);
};
return Particle;
})();
/*
* ParticlePool class
*/
var ParticlePool = (function () {
var particles,
firstActive = 0,
firstFree = 0,
duration = settings.particles.duration;
function ParticlePool(length) {
// create and populate particle pool
particles = new Array(length);
for (var i = 0; i < particles.length; i++)
particles[i] = new Particle();
}
ParticlePool.prototype.add = function (x, y, dx, dy) {
particles[firstFree].initialize(x, y, dx, dy);
// handle circular queue
firstFree++;
if (firstFree == particles.length) firstFree = 0;
if (firstActive == firstFree) firstActive++;
if (firstActive == particles.length) firstActive = 0;
};
ParticlePool.prototype.update = function (deltaTime) {
var i;
// update active particles
if (firstActive < firstFree) {
for (i = firstActive; i < firstFree; i++)
particles[i].update(deltaTime);
}
if (firstFree < firstActive) {
for (i = firstActive; i < particles.length; i++)
particles[i].update(deltaTime);
for (i = 0; i < firstFree; i++) particles[i].update(deltaTime);
}
// remove inactive particles
while (
particles[firstActive].age >= duration &&
firstActive != firstFree
) {
firstActive++;
if (firstActive == particles.length) firstActive = 0;
}
};
ParticlePool.prototype.draw = function (context, image) {
// draw active particles
if (firstActive < firstFree) {
for (i = firstActive; i < firstFree; i++)
particles[i].draw(context, image);
}
if (firstFree < firstActive) {
for (i = firstActive; i < particles.length; i++)
particles[i].draw(context, image);
for (i = 0; i < firstFree; i++) particles[i].draw(context, image);
}
};
return ParticlePool;
})();
/*
* Putting it all together
*/
(function (canvas) {
var context = canvas.getContext("2d"),
particles = new ParticlePool(settings.particles.length),
particleRate =
settings.particles.length / settings.particles.duration, // particles/sec
time;
// get point on heart with -PI <= t <= PI
function pointOnHeart(t) {
return new Point(
160 * Math.pow(Math.sin(t), 3),
130 * Math.cos(t) -
50 * Math.cos(2 * t) -
20 * Math.cos(3 * t) -
10 * Math.cos(4 * t) +
25
);
}
// creating the particle image using a dummy canvas
var image = (function () {
var canvas = document.createElement("canvas"),
context = canvas.getContext("2d");
canvas.width = settings.particles.size;
canvas.height = settings.particles.size;
// helper function to create the path
function to(t) {
var point = pointOnHeart(t);
point.x =
settings.particles.size / 2 +
(point.x * settings.particles.size) / 350;
point.y =
settings.particles.size / 2 -
(point.y * settings.particles.size) / 350;
return point;
}
// create the path
context.beginPath();
var t = -Math.PI;
var point = to(t);
context.moveTo(point.x, point.y);
while (t < Math.PI) {
t += 0.01; // baby steps!
point = to(t);
context.lineTo(point.x, point.y);
}
context.closePath();
// create the fill
context.fillStyle = "#ea80b0";
context.fill();
// create the image
var image = new Image();
image.src = canvas.toDataURL();
return image;
})();
// render that thing!
function render() {
// next animation frame
requestAnimationFrame(render);
// update time
var newTime = new Date().getTime() / 1000,
deltaTime = newTime - (time || newTime);
time = newTime;
// clear canvas
context.clearRect(0, 0, canvas.width, canvas.height);
// create new particles
var amount = particleRate * deltaTime;
for (var i = 0; i < amount; i++) {
var pos = pointOnHeart(Math.PI - 2 * Math.PI * Math.random());
var dir = pos.clone().length(settings.particles.velocity);
particles.add(
canvas.width / 2 + pos.x,
canvas.height / 2 - pos.y,
dir.x,
-dir.y
);
}
// update and draw particles
particles.update(deltaTime);
particles.draw(context, image);
}
// handle (re-)sizing of the canvas
function onResize() {
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
}
window.onresize = onResize;
// delay rendering bootstrap
setTimeout(function () {
onResize();
render();
}, 10);
})(document.getElementById("pinkboard"));
</script>
</body>
</html>
```
![示例图片](https://devbit-static.oss-cn-beijing.aliyuncs.com/devbit-static/img/heart.png)