C语言实现求定积分的方法

本文实例讲述了C语言实现求定积分的方法。分享给大家供大家参考。具体实现方法如下：


#include <cmath>  
#include <cstdio>

#define ACC 1000

float solve(float (*p)(float),float up,float down,int acc);

float fun_exp(float x);

float fun_qua(float x);

void main(){

char selection;

float up,down;

while(printf("请选择被积函数:\n"),printf("1、exp(x) 2、x+1 \n"),scanf("%c",&selection),selection != '#'){

printf("请输入积分上下限: ");

scanf("%f,%f",&up,&down);

switch(selection){

case '1':

printf("结果是: %4.4f\n",solve(fun_exp,up,down,ACC));

break;

case '2':

printf("结果是: %4.4f\n",solve(fun_qua,up,down,ACC));

break;

}

float solve(float (*p)(float),float up,float down,int acc){

float sum,base,area;

area = 0;

sum = 0;

base = (up-down)/acc;

for(int i=0; i

area = base*((*p)(down+i*base));

sum+=area;

}

return sum;

}

float fun_exp(float x){

return exp(x);

}

float fun_qua(float x){ //一元二次方程 quadratics

return x+1;

}