View Compilation Error

0_0_13195567_25404.cpp: In function 'int main()':
0_0_13195567_25404.cpp:17:21: error: 'strcmp' was not declared in this scope
      if(strcmp(s,"+")==0)
                     ^
0_0_13195567_25404.cpp:31:21: error: 'strcmp' was not declared in this scope
      if(strcmp(s,"=")==0){
                     ^