View Compilation Error

0_0_24219030_27566.cpp: In function 'int main()':
0_0_24219030_27566.cpp:131:39: error: 'strcmp' was not declared in this scope
     while (gets(expr)&&strcmp(expr,"0")!=0) {
                                       ^
0_0_24219030_27566.cpp:134:51: error: 'strlen' was not declared in this scope
         auto ast = parser(expr, expr + strlen(expr));
                                                   ^