infix to postfix notation

[momotaro]

this is my code:

 void ConvertToPostFix(char *exp) 
 
{
 
int i;
 
stack *s;
 
StackEntry *item;
 
s = CreatStack(&s);
 
for(i = 0; i != '\n'; i++)
 
{
 
if(isalnum(exp[i]))
 
printf("%c", exp[i]);
 
else if(StackEmpty(s))
 
Push(exp[i], s);
 
else
 
{
 
while(check(exp[i], s->entry[s->top]))
 
Pop(item, s);
 
if(check(exp[i], s->entry[s->top]))
 
Push(exp[i], s);
 
}
 
}
 
}
 
 

the error message is :
[size=1]main.obj : error LNK2019: unresolved external symbol _check referenced in function _ConvertToPostFix

and:
[size=1]fatal error LNK1120: 1 unresolved externals

in addition to some WARNINGS that i realy danot know how to avoid them...

WARNINGS:
1: warning C4047: 'function' : 'int *' differs in levels of indirection from 'int **__w64 ' main.c 18


2: warning C4024: 'DisplayMenu' : different types for formal and actual parameter 1 c:\main.c 18

3: warning C4047: 'function' : 'int *' differs in levels of indirection from 'int **__w64 ' main.c 19

4: warning C4024: 'DoCommand' : different types for formal and actual parameter 1 cmain.c 19

5: warning C4047: 'function' : 'stack *' differs in levels of indirection from 'stack **__w64 ' main.c 58

6: main.c(58) : warning C4024: 'CreatStack' : different types for formal and actual parameter 1

7: main.c(68) : warning C4700: uninitialized local variable 'item' used

[tracethepath]

 
for(i = 0; i != '\n'; i++)
 
 

basic problem i think is i cant be compared to a character type...
i is an integer
what you should do is

for(int i=0; exp[i]!='\0'; i++)
 

[weaknessforcats]

i can be compared to an integer because it is an integer.

Read up on arithmetic conversions an you will see that in expressions the first thing the compiler does is convert all char and short to int. Additional rules proceed form there.

I am more interetd in the fact that check function can't be found. Maybe that could be posted. That's what's causing the LNK2019.

All of the warnings are avoidable. You never allow warnings in your code. Often before a release, the compiler is set to convert all warnings to errors.

[momotaro]

this is my all new peace of code but am still havin unexpecetd result:

input: 1+2-3/4 normal output: 12+34/- code result: 12+34/1+2-3/4

this is my code:

void ConvertToPostFix(char *exp)
 
{
 
int i;
 
stack *s;
 
StackEntry *item;
 
s = CreatStack(&s);
 
for(i = 0; exp[i] != '\0'; i++)
 
{
 
if(isalnum(exp[i]))
 
printf("%c", exp[i]);
 
else if(StackEmpty(s))
 
Push(exp[i], s);
 
else
 
{
 
while(check(exp[i], s->entry[s->top]) && !StackEmpty(s))
 
{
 
Pop(&item, s);
 
printf("%c", item);
 
}
 
if(!check(exp[i], s->entry[s->top]))
 
Push(exp[i], s);
 
}
 
}
 
}
 
 

[momotaro]

I think that the problem first is that this line of code id not executed:

 if(!check(exp[i], s->entry[s->top])) 
Push(exp[i], s);