View Compilation Error

0_0_33616727_2510.cpp: In function 'int main()':
0_0_33616727_2510.cpp:31:40: error: too few arguments to function 'double integral(double, double, double)'
          printf("%.3f\n",2*integral(l,r));
                                        ^
0_0_33616727_2510.cpp:17:8: note: declared here
 double integral(double l,double r,double res)//自适应
        ^