View Compilation Error

0_0_21367209_17482.cpp: In function 'int main()':
0_0_21367209_17482.cpp:23:19: error: 'c' was not declared in this scope
      if(a+b>mid)l=c;
                   ^
0_0_21367209_17482.cpp:24:24: error: 'c' was not declared in this scope
      else if(a+b<mid)r=c;
                        ^
0_0_21367209_17482.cpp:25:26: error: 'c' was not declared in this scope
      else {printf("%d\n",c);return 0;}
                          ^