/in/lab4.c: In function 'main':
/in/lab4.c:23:27: warning: variable 'db' set but not used [-Wunused-but-set-variable]
     char ch[100],dis[100],db[100];
                           ^~
/tmp/ccfQ2MO2.o: In function `main':
lab4.c:(.text.startup+0x3c7): undefined reference to `ConvertToken'
lab4.c:(.text.startup+0x401): undefined reference to `RPNCalculate'
lab4.c:(.text.startup+0x420): undefined reference to `SetVar'
collect2: error: ld returned 1 exit status