View Compilation Error

0_0_31071829_277.cpp: In function 'int main()':
0_0_31071829_277.cpp:37:27: error: 'fabs' was not declared in this scope
  float len1=fabs(x[0]-x[1]),height1=fabs(y[0]-y[1]);
                           ^
0_0_31071829_277.cpp:41:20: error: 'height1' was not declared in this scope
  else if(ymax-ymin>height1+height2)
                    ^
0_0_31071829_277.cpp:41:28: error: 'height2' was not declared in this scope
  else if(ymax-ymin>height1+height2)
                            ^