Question

Hey guys, i’m working on a program that gets a postfix expression and calculates it..

I have two functions:

1. Converts infix to postfix
2. Calculate the postfix

When I try small expressions, like 1+1 or (1+1)*1, it works fine
but when i use all the operands I get something nasty,

Here is the example:
2*2/2+1-1
gets something like:
222/*11-+T_CHECKÖÐ7?█Ã

If you see, the expression is right until the ‘T’

I believe it’s some parameter mistake, so i’ll put the header and return values here

1st)

char* convert(char *infix);
char *post = (char *)malloc(sizeof(char)*tamP);
return post;

2nd)

int evaluate(char *postfix)
while (*postfix != '\0')
return result;

Caller)

char* post = convert(infix);
result = evaluate(post);

Thanks

Answer 1

It is possible that you are not adding the ‘\0’ character at the end of ‘post’ (after the last sensible character) in the convert(char*) function. That’s one reason I can think of.
Try setting the complete string to ‘\0’ before you do anything with it:

memset(post, 0, tamP);

should do.