double fun(int n){ double s, t; int i; s=1.0; t=1.0; for(i=1;i<=n;i++)//这里应该是i++ { t=t*i/(2*i+1); s+=t; } return s;}int main(int argc, char *argv[]){ printf("\n %12.10lf", fun(20)); return 0;}
s=0.0; t=1.0;这里改为s=1