View Compilation Error

0_0_17483677_17549.cpp: In function 'void GetId()':
0_0_17483677_17549.cpp:33:32: error: 'strcmp' was not declared in this scope
         if(strcmp(id,keyword[i]) == 0){
                                ^
0_0_17483677_17549.cpp: In function 'void ScanMulCom()':
0_0_17483677_17549.cpp:54:29: error: 'strlen' was not declared in this scope
             len = strlen(str);
                             ^
0_0_17483677_17549.cpp: In function 'int main()':
0_0_17483677_17549.cpp:75:29: error: 'strcmp' was not declared in this scope
         if(strcmp(str,"####") == 0){
                             ^
0_0_17483677_17549.cpp:80:25: error: 'strlen' was not declared in this scope
         len = strlen(str);
                         ^