View Compilation Error

0_0_15515185_31748.cpp: In function 'void creat(char*, int)':
0_0_15515185_31748.cpp:14:23: error: 'strlen' was not declared in this scope
     int len=strlen(str);
                       ^
0_0_15515185_31748.cpp: In function 'int find(char*)':
0_0_15515185_31748.cpp:40:23: error: 'strlen' was not declared in this scope
     int len=strlen(str);
                       ^
0_0_15515185_31748.cpp: In function 'int main()':
0_0_15515185_31748.cpp:86:25: error: 'strlen' was not declared in this scope
         int len=strlen(t);
                         ^
0_0_15515185_31748.cpp:101:37: error: 'memset' was not declared in this scope
                 memset(f,0,sizeof(f));
                                     ^