View Compilation Error

0_0_33515528_31115.cpp: In function 'int main()':
0_0_33515528_31115.cpp:11:21: error: 'strlen' was not declared in this scope
   int len = strlen(a);
                     ^
0_0_33515528_31115.cpp:109:4: error: 'cas' was not declared in this scope
    cas
    ^
0_0_33515528_31115.cpp:109:4: error: expected '}' at end of input
0_0_33515528_31115.cpp:109:4: error: expected '}' at end of input
0_0_33515528_31115.cpp:109:4: error: expected '}' at end of input
0_0_33515528_31115.cpp:109:4: error: expected '}' at end of input