View Compilation Error

0_0_16825005_11310.cpp: In function 'int main()':
0_0_16825005_11310.cpp:9:22: error: 'strcmp' was not declared in this scope
   if (strcmp(a,"<br>")==0)
                      ^
0_0_16825005_11310.cpp:15:21: error: 'strcmp' was not declared in this scope
   if(strcmp(a,"<hr>")==0)
                     ^
0_0_16825005_11310.cpp:28:13: error: 'strlen' was not declared in this scope
   l=strlen(a);
             ^