View Compilation Error

0_0_24291037_11784.cpp: In function 'void cleanlastzero(char*)':
0_0_24291037_11784.cpp:5:25: error: 'strlen' was not declared in this scope
     int len = strlen(str), digit_place = -1;
                         ^
0_0_24291037_11784.cpp:8:13: error: 'digit_place' was not declared in this scope
             digit_place = i;
             ^
0_0_24291037_11784.cpp:12:9: error: 'digit_place' was not declared in this scope
     if (digit_place == -1)
         ^
0_0_24291037_11784.cpp: In function 'int main()':
0_0_24291037_11784.cpp:28:30: error: 'strcmp' was not declared in this scope
         if (strcmp(str1, str2)==0)
                              ^