怎样编写c语言积分函数用梯形法求函数f（x

#include float f(float x) { return x*x+2*x+1; } void main() { float a,b,len,F=0;// int n,i; printf("Please input a,b: "); scanf("%f%f",&a,&b); printf("Please input n: "); scanf("%d",&n); len=(a+