View Compilation Error

0_0_24483608_20035.cpp: In function 'int main()':
0_0_24483608_20035.cpp:19:18: error: 'strcmp' was not declared in this scope
   if (strcmp(b, c) == 0)
                  ^
0_0_24483608_20035.cpp:27:24: error: 'strcmp' was not declared in this scope
    if (strcmp(a[i].s, b) == 0)
                        ^
0_0_24483608_20035.cpp:32:24: error: 'strcmp' was not declared in this scope
    if (strcmp(a[i].s, c) == 0)
                        ^