View Compilation Error

0_0_23614159_9561.cpp: In function 'bool cmp2(const student&, const student&)':
0_0_23614159_9561.cpp:19:42: error: 'strcmp' was not declared in this scope
             return strcmp(s2.Name,s1.Name)>0?1:0;
                                          ^
0_0_23614159_9561.cpp: In function 'int cmp(const void*, const void*)':
0_0_23614159_9561.cpp:39:42: error: 'strcmp' was not declared in this scope
             return strcmp(c->Name,d->Name);
                                          ^
0_0_23614159_9561.cpp: In function 'int main()':
0_0_23614159_9561.cpp:73:21: error: 'sort' was not declared in this scope
     sort(s, s+i,cmp2);
                     ^