View Compilation Error

0_0_24342866_17212.cpp: In function 'int main()':
0_0_24342866_17212.cpp:17:29: error: 'strlen' was not declared in this scope
         for(i=0;i<strlen(str);++i)
                             ^
0_0_24342866_17212.cpp:26:29: error: 'strlen' was not declared in this scope
         for(i++;i<strlen(str);++i)
                             ^
0_0_24342866_17212.cpp:35:31: error: 'strlen' was not declared in this scope
         for(i++; i< strlen(str); ++i)
                               ^