View Compilation Error

0_0_32847582_22168.cpp: In function 'int main()':
0_0_32847582_22168.cpp:19:36: error: 'memset' was not declared in this scope
    memset(m_hash, 0, sizeof(m_hash));
                                    ^
0_0_32847582_22168.cpp:21:46: error: 'strcmp' was not declared in this scope
    while(gets(source) && strcmp(source, "END"))
                                              ^
0_0_32847582_22168.cpp:23:22: error: 'strlen' was not declared in this scope
     n = strlen(source);
                      ^
0_0_32847582_22168.cpp:35:46: error: 'strcmp' was not declared in this scope
    while(gets(source) && strcmp(source, "END"))
                                              ^
0_0_32847582_22168.cpp:37:22: error: 'strlen' was not declared in this scope
     n = strlen(source);
                      ^