fix logical error in infix to postfix notation program

[SUVIR]

#include<stdio.h>
#include<ctype.h>
#include<stdlib.h>
#define max 100
int stackpoint=0;
int stackbuff[max];
void push(int a);
int pop();
char getop(char infix[max]);
int precedance(char l);
void intopostfix(char infix[max],float postfix[max]);
void main()
{
    int i=0;
    float postfix[max];
    char infix[max];
    intopostfix(infix,postfix);
    printf("\n POSTFIX NOTATION IS\n");
    while(postfix[i]!='#')
    {if(postfix[i]!='(');
    printf("%f",postfix[i++]);i++;}
}
void intopostfix(char infix[max],float postfix[max])
{
    char l;
     int k=0,j;
     float operand;
     push('#');
    while((l=getop(infix))!=EOF)
    {
      if(l!='#'&&l!='e')
      {
      switch(l)
      {
      case 'o':
       operand=atof(infix);
       postfix[k++]=operand;
       break;
      case '(': case '^': case '*': case'/': case'%': case '+': case '-':
       if((j=precedance(l)>=0))
             push(l);
        while(j=precedance(l)<0)
        postfix[k++]=pop();
        break;
       case ')':
        break;
        default :
        printf("INVALID STATEMENT%c\n",l);
        break;
      }
      }
      else if(l=='#')
      {
          postfix[k]='#';
          return;
      }
      else if(l=='e');
    }
}
char getop(char infix[max])
{
    int i=0;
    char c;
    c=getchar();
    if(c=='('||c=='^'||c=='*'||c=='/'||c=='+'||c=='+'||c=='#')
       return c;
       if(isdigit(c)||c=='.')
       {
        while(isdigit(infix[i++]=c))
        {c=getchar();}
    if(c=='.')
    {infix[i++]=c;
        while(isdigit(infix[i++]=c=getchar()));
    }

    infix[i]='\0';
    return 'o';
       }
       else
       return 'e';

}
void push(int oprater)
{
    if(stackpoint<max)
    {
        stackbuff[stackpoint++]=oprater;
    }
    else
    {
       printf("STACK LIMIT EXCEED\n");
    }
}
int pop()
{
    int temp;
    if(stackpoint>0)
       return stackbuff[--stackpoint];

    else
    {
       printf("STACK EMPTY\n");
       return 0.0;
    }
}
int precedance(char l)
{
   int precedbuff[3][8]={{'(','^','*','/','%','+','-','#'},
                         {5,4,3,3,3,2,2,0},
                         {1,4,3,3,3,2,2,0}},j,val1,val2;

   for(j=0;j<8;j++)
   {
       if(l==precedbuff[0][j])
       val1=precedbuff[1][j];
       if(stackbuff[stackpoint]==precedbuff[0][j])
       val2=precedbuff[2][j];
   }
   return val1-val2;
}

cant fix the logical error pls help

[SUVIR]

do anyone knows what to fix for output to work

[dmh2000]

you need to be a little more specific about what logical error you are talking about. and question #1 : does your program compile without errors or warnings? if not, then fix that first.

[SUVIR]

there no syntax error in program and program is compiling but when intopostfix function is called in it getop is called which should return desired value i.e if
value entered is digit it returns 'o' and if any operator should return the operater else return 'e'implies error.But dont know for wat reason getop is only returning 'e' inspite of entering values of operand and operator using getchar function.and dont know for what reason while loop in intopostfix is not terminating on EOF NOTATION.
LASTLY precedance function to note the precedance of a operater is not called .
hence on compiling program takes infix notation but dont gives output as specified in main as intopostfix function do not terminate due to infinite while loop maybe

[anduril462]

while(j=precedance(l)<0)Turn the warning level up on your compiler, your code is NOT error and warning free. Even if it has no syntax errors and compiles, it may not be doing what you think:

$ make calc
gcc -Wall -g -std=c99  -lssl -lm -lpthread -lcurses -lefence  calc.c   -o calc
calc.c:12: warning: return type of ‘main’ is not ‘int’
calc.c: In function ‘intopostfix’:
calc.c:42: warning: suggest parentheses around assignment used as truth value
calc.c: In function ‘pop’:
calc.c:96: warning: unused variable ‘temp’

[list]
First, it's int main(void) and return an integer at the end, usually 0. Read this link. I sure hope you aren't using void main because you're compiling with Turbo C. If you are, get a more modern compiler, like Pelles C, Code::Blocks with MinGW or Visual C++ Express.

Then, take a look at this line:

while(j=precedance(l)<0)

That is equivalent to

while(j=(precedance(l)<0))

Notice that the parentheses are around the comparison -- you are assigning the boolean result (0 or 1) of the less-than comparison to j. You are not assigning the result of precedance(l) to j, then comparing that to 0, which would look like:

while((j=precedance(l))<0)

I'm not sure which way you intend it to work, but you should be explicit in such cases. You use complex conditionals like that in several places, make sure they're all doing what you want.

[hk_mp5kpdw]

and dont know for what reason while loop in intopostfix is not terminating on EOF NOTATION.

...

void intopostfix(char infix[max],float postfix[max])
{
    char l;
    int k=0,j;
    float operand;
    push('#');
    while((l=getop(infix))!=EOF)
    {
...

char getop(char infix[max])
{
    int i=0;
    char c;
    c=getchar();
    if(c=='('||c=='^'||c=='*'||c=='/'||c=='+'||c=='+'||c=='#')
       return c;

The getchar function returns an int, not a char. Your getop function returns this char value and tries to compare against EOF which is problematic. At the least, getop needs to return an int, not a char; variable c in getop needs to be an int; variable l in function intopostfix needs to be an int.