View Compilation Error

0_0_13651083_11218.cpp: In function 'int main()':
0_0_13651083_11218.cpp:74:16: error: 'time' was not declared in this scope
 srand(time(NULL));
                ^
0_0_13651083_11218.cpp:82:17: error: 'strlen' was not declared in this scope
 int n = strlen(s);
                 ^
0_0_13651083_11218.cpp:91:23: error: 'memset' was not declared in this scope
 memset(f, 0, sizeof(f));
                       ^