View Compilation Error

0_0_32235505_31724.cpp: In function 'int main()':
0_0_32235505_31724.cpp:50:31: error: 'memset' was not declared in this scope
           memset(f,1,sizeof(f));
                               ^
0_0_32235505_31724.cpp:53:21: error: 'strlen' was not declared in this scope
           l=strlen(c);
                     ^