View Compilation Error

0_0_17886128_28316.cpp: In function 'int main()':
0_0_17886128_28316.cpp:25:25: error: 'strlen' was not declared in this scope
         int len=strlen(s);
                         ^
0_0_17886128_28316.cpp:38:46: error: 'strcpy' was not declared in this scope
                     strcpy(na[++num].str,str1);
                                              ^