View Compilation Error

0_0_35048064_10048.cpp: In function 'int mmm(char*)':
0_0_35048064_10048.cpp:11:22: error: 'strcmp' was not declared in this scope
   if(!strcmp(ls,hk[a]))
                      ^
0_0_35048064_10048.cpp: In function 'int main()':
0_0_35048064_10048.cpp:22:37: error: 'strcmp' was not declared in this scope
   while(scanf("%s",&h)&&strcmp(h,"+"))
                                     ^
0_0_35048064_10048.cpp:27:37: error: 'strcmp' was not declared in this scope
   while(scanf("%s",&h)&&strcmp(h,"="))
                                     ^