这是我写的#include <stdio.h>double f(int n){ double j,k,l; j=(2*n)/(2*n-1); k=(2*n)/(2*n+1); l=j*k; return(l);}int main(){ int i=1; double term=1,a=1; while(term>1.0e-5){ a=a*term; term=f(i); i++; } printf("%f",a);} 不知道哪不对