View Compilation Error

0_0_24176118_12707.cpp: In function 'int main(int, char**)':
0_0_24176118_12707.cpp:21:21: error: 'strcmp' was not declared in this scope
    if(strcmp(qu,"in")==0)
                     ^
0_0_24176118_12707.cpp:28:22: error: 'strcmp' was not declared in this scope
    if(strcmp(qu,"out")==0)
                      ^
0_0_24176118_12707.cpp:34:24: error: 'strcmp' was not declared in this scope
    if(strcmp(qu,"query")==0)
                        ^