2421: C语言习题 矩形法求定积分
时间限制: 1 Sec 内存限制: 128 MB
提交: 354 解决: 234
题目描述
写一个用矩形法求定积分的通用函数，分别求
（说明: sin,cos,exp已在系统的数学函数库中，程序开头要用#include<cmath>）。
输入
输入求sin(x) 定积分的下限和上限
输入求cos(x) 定积分的下限和上限
输入求exp(x) 定积分的下限和上限
输出
求出sin(x)的定积分
求出cos(x)的定积分
求出exp(x)的定积分
样例输入
0 1
0 1
0 1
样例输出
The integral of sin(x) is :0.48
The integral of cos(x) is :0.83
The integral of exp(x) is :1.76
提示
主函数已给定如下，提交时不需要包含下述主函数
/* C代码 */
int main()
{
float integral(float (*p)(float),float a,float b,int n);
float a1,b1,a2,b2,a3,b3,c,(*p)(float);
float fsin(float);
float fcos(float);
float fexp(float);
int n=20;
scanf("%f%f",&a1,&b1);
scanf("%f%f",&a2,&b2);
scanf("%f%f",&a3,&b3);
p=fsin;
c=integral(p,a1,b1,n);
printf("The integral of sin(x) is :%.2f\n",c);
p=fcos;
c=integral(p,a2,b2,n);
printf("The integral of cos(x) is :%.2f\n",c);
p=fexp;
c=integral(p,a3,b3,n);
printf("The integral of exp(x) is :%.2f\n",c);
return 0;
}
/* C++代码 */
int main()
{
float integral(float (*p)(float),float a,float b,int n);
float a1,b1,a2,b2,a3,b3,c,(*p)(float);
float fsin(float);
float fcos(float);
float fexp(float);
int n=20;
cin>>a1>>b1;
cin>>a2>>b2;
cin>>a3>>b3;
cout<<setiosflags(ios::fixed);
cout<<setprecision(2);
p=fsin;
c=integral(p,a1,b1,n);
cout<<"The integral of sin(x) is :"<<c<<endl;
p=fcos;
c=integral(p,a2,b2,n);
cout<<"The integral of cos(x) is :"<<c<<endl;;
p=fexp;
c=integral(p,a3,b3,n);
cout<<"The integral of exp(x) is :"<<c<<endl;
return 0;
}
迷失在幽谷中的鸟儿，独自飞翔在这偌大的天地间，却不知自己该飞往何方……
#include <stdio.h>
#include <math.h>
float integral(float (*p)(float),float a,float b,int n)
{
float s=0.0,i,w;
w=(b-a)/n;
for(i=a; i<=b; i+=w)
s+=p(i+w)*w;
return s;
}
float fsin(float a)
{
return sin(a);
}
float fcos(float a)
{
return cos(a);
}
float fexp(float a)
{
return exp(a);
}
int main()
{
float integral(float (*p)(float),float a,float b,int n);
float a1,b1,a2,b2,a3,b3,c,(*p)(float);
float fsin(float);
float fcos(float);
float fexp(float);
int n=20;
scanf("%f%f",&a1,&b1);
scanf("%f%f",&a2,&b2);
scanf("%f%f",&a3,&b3);
p=fsin;
c=integral(p,a1,b1,n);
printf("The integral of sin(x) is :%.2f\n",c);
p=fcos;
c=integral(p,a2,b2,n);
printf("The integral of cos(x) is :%.2f\n",c);
p=fexp;
c=integral(p,a3,b3,n);
printf("The integral of exp(x) is :%.2f\n",c);
return 0;
}