View Compilation Error

0_0_38284088_17441.cpp:12:22: error: expected ',' or '...' before '.' token
 double solve(double l.double r){
                      ^
0_0_38284088_17441.cpp: In function 'double solve(double)':
0_0_38284088_17441.cpp:14:14: error: 'r' was not declared in this scope
  while(l+eps<r){ //r-l>1e-7 误差允许范围 
              ^
0_0_38284088_17441.cpp:16:20: error: 'rmid' was not declared in this scope
   if(val(lmid)<val(rmid)){
                    ^
0_0_38284088_17441.cpp: In function 'int main()':
0_0_38284088_17441.cpp:31:32: error: too many arguments to function 'double solve(double)'
   printf("%.4f\n",solve(0,100.0)); 
                                ^
0_0_38284088_17441.cpp:12:8: note: declared here
 double solve(double l.double r){
        ^