View Compilation Error

0_0_30829269_11492.cpp: In function 'bool isPopStack(char*, char*)':
0_0_30829269_11492.cpp:7:51: error: 'strlen' was not declared in this scope
  if( !pPushStack || !pPopStack ||strlen(pPushStack) !=strlen(pPopStack))//异常处理
                                                   ^
0_0_30829269_11492.cpp: At global scope:
0_0_30829269_11492.cpp:26:11: error: '::main' must return 'int'
 void main()
           ^