Program Works only debug mode but not in normal exe (using c lion)?

Question

SO i created a program that converts from infix to post fix and prefix which works just fine. The thing is that I am using C-LION which has its own debugger that allows me to go step by step and I do that the program works fine and outputs the expected results BUT then when I run it normally IT DOES NOT WORK AND GIVES ME A "main.c not working " ERROR.

This the main function that has the menu:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <tgmath.h>

char*infixToPostfix(char *infinx);
char* postixToinfix(char *infinx);
char* postixToprefix(char *infinx);
char* prefixToinfix(char *infinx);
char* prefixTopostfix(char *infinx);
char* infixToPrefix(char *infinx);
char*evaluate(char *infinx );
int exp_det(char*exp);
typedef struct node
{
    char *op;
    int  p;
    struct node *next; /* Pointer to the next node. Notice that the
    existence of the structure tag enables us to declare its type. */
} node;
node *head=NULL; /* Global pointer that always points to the head of the
    stack. */
int precedence(char symbol);
void add_stack(const node *p);
void pop(void);
int main(void)
{
    char postfix[100];
    int choice;
    //converting from ininfinx to postfix
    printf("\t\t***** Conversion Calculator 1.0 ******\t\t\n");
    printf("\t\t1.Convert\n\t\t2.Evaluate\n\t\t3.Exit\nEnter Choice : ");
    scanf("%d",&choice);
    //switch (choice){
        if (choice==1) {
            printf("\n\t\t1.Input from File\n\t\t2.standered  input\nEnter Choice :");
            int ch2;
            scanf("%d", &ch2);
            switch (ch2) {
                case 1:
                    printf("FILE MANGAMENT STILL NOT DONE !!!");
                    break;
                case 2:
                    printf("Enter Expression : ");
                    char line[256];


                    scanf(" %[^\n]s", postfix);
                    char in2[100] = {'\0'};
                    char in3[100] = {'\0'};
                    char *conv;
                    char *conv2;

                    strcpy(in2, postfix);
                    strcpy(in3, postfix);
                    int exp = exp_det(in2);

                    if (exp == 1) {
                        printf("\nThis is a Prefix expression do you want to\n\t\t1.Infix\n\t\t2.Postfix\n\t\t3.Both\nEnter Choice :");
                        int ch3;
                        scanf("%d", &ch3);
                        switch (ch3) {
                            case 1:
                                conv = prefixToinfix(in3);
                                printf("Expression in Infix form: %s \n", in3);
                                break;
                            case 2:
                                conv = prefixTopostfix(in3);
                                printf("Expression in Postfix form: %s \n", in3);
                                break;
                            case 3:
                                conv = prefixToinfix(in3);
                                conv2 = prefixTopostfix(postfix);
                                printf("Expression in Infix form: %s \n", conv);
                                printf("Expression in Postfix form: %s \n", conv2);
                                break;
                            default:
                                printf("ERROROR WHEN EXPRESSION IN PREFIX ");

                                break;
                        }
                    } else if (exp == 2) {
                        printf("\nThis is a Infix expression do you want to\n\t\t1.Prefix\n\t\t2.Postfix\n\t\t3.Both\nEnter Choice :");
                        int ch3;
                        scanf("%d", &ch3);
                        switch (ch3) {
                            case 1:
                                printf("Expression in prefix form: %s \n", infixToPrefix(postfix));
                                break;
                            case 2:
                                printf("Expression in Postfix form: %s \n", infixToPostfix(postfix));
                                break;
                            case 3:
                                printf("Expression in prefix form: %s \n", infixToPrefix(postfix));
                                printf("Expression in Postfix form: %s \n", infixToPostfix(postfix));
                                break;
                            default:
                                printf("ERROROR R");

                                break;
                        }
                    } else if (exp == 3) {
                        printf("This is a Postfix expression do you want to\n\t\t1.Infix\n\t\t2.Prefix\n\t\t3.Both\nEnter Choice :");
                        int ch3;
                        scanf("%d", &ch3);
                        switch (ch3) {
                            case 1:
                                printf("Expression in Infix form: %s \n", postixToinfix(postfix));
                                break;
                            case 2:
                                printf("Expression in prefix form: %s \n", postixToprefix(postfix));
                                break;
                            case 3:
                                printf("Expression in Infix form: %s \n", postixToinfix(postfix));
                                printf("Expression in Prefix form: %s \n", postixToprefix(postfix));
                                break;
                            default:
                                printf("ERROR... 3:(\n");
                                break;
                        }
                    }
                    break;//for the switch with ch2 case 1
                default:
                    printf("ERROR... 2:(\n");
                    break;
            }
            //break;
        }if(choice==2) {
        printf("Enter Expression : ");

        scanf(" %[^\n]s", postfix);
        char in2[100] = {'\0'};
        char in3[100] = {'\0'};
        char *conv;
        char *conv2;

        strcpy(in2, postfix);
        conv = evaluate(in2);
        printf("\nExpression evaluated = %s \n", conv);
        //break;
    }if(choice==3) {
        printf("BYE...... :D\n");


    }

    system("PAUSE");
}

OK Now after much trials I am starting to think that the problem is in the conversion itself. This is one of the functions i am using for me it looks fine. If anyone has another opinion help is greatly appropriated.

char* infixToPostfix(char *infinx){
char* token;

char * infinx1=malloc(sizeof(infinx)+1);

infinx1=strcpy(infinx1,infinx);

token = strtok(infinx1," ");

char* res;
res=malloc(sizeof(infinx)+sizeof(head->op)*strlen(infinx));

strcpy(res," ");

if(*token=='\n' ){token=strtok(NULL," ");}

while( token != NULL ) {

    node n;
    n.op=token;
    n.p=precedence(*token);
    if(isalpha(*token) || isdigit(*token)){
        // strcat(result,infinx[i]);
        //printf("%c",infinx[i]);

        res=strcat(res,token);
        res=strcat(res," ");
    }
        //case when encounter a left paranthessisis
    else if(*token=='(' || *token==')'){
        if (*token=='('){
            add_stack(&n);
        }else if(*token==')') {

            while (*head->op != '(') {
                // strcat(result, n.op);
                //printf("%c",(char)head->op);
                res=strcat(res,head->op);
                res=strcat(res," ");
                pop();
            }
            pop();
        }
    }
        //if head if null meaning the stack is empty or if the presendance of the head is less thatn or equal to new character
    else if(head==NULL || head->p < n.p ){
        if (head->p == n.p){}
        add_stack(&n);
    }
        //in case the head has higher presendance he we pop and print untill we reach the same presedance
    else  {
        while( head!=NULL && head->p >= n.p){
            //strcat(result,n.op);
            //printf("%c",(char)head->op);
            res=strcat(res,head->op);
            res=strcat(res," ");
            pop();
        }
        add_stack(&n);
    }
    token=strtok(NULL," ");
}
while(head!=NULL){
    //strcat(result,head->op);
    //printf("%c",(char)head->op);
    res=strcat(res,head->op);
    res=strcat(res," ");
    pop();
}
return res;

}

Answer 1

This is the answer to your question "So your saying I should define them outside the switch statement?" which reflects correctly one of the problems in your code.

Either: You can define them outside to solve the issue.

Or: You can introduce appropriate block scopes to solve the issue.

As the former is trivial, I will elaborate the latter:

1. Scope and Variables

The life-time of a local variable starts at its declaration and ends with surrounding block scope.

Example:

int main()
{
  int a = 0; /* a starts to live. */
  { /* new scope */
    int b = 1; /* b starts to live */
    int a = 2; /* a new a starts to live. (The one of out scope is eclipsed.) */
  } /* Life of b and the inner a ends. The eclipsed outer a becomes visible again. */
  return 0;
}

2. switch and case

In opposition to other languages (like e.g. Pascal), the C switch statement is rather a "goto depending on expression" than a multiway branching with multiple alternatives. (This does not mean that switch cannot be used for the latter but it can be used different as well.) (Please, see Wikipedia: Control Flow: 5.2 Case and switch statements to understand what I mean.)

Imagine the following (wrong) code:

#include <stdio.h>

int main()
{
  goto L1;
  int i = 1;
L1:
  printf("%d\n", i);
  return 0;
}

The goto L1; skips the declaration of int i = 1; but after L1: it is used in printf() – ouch!

Out of curiosity, I tried it in ideone.com – it compiled and ran without complaints. Output was 0 although it could have been as well 1, 2, or any other number which can be stored as int.

This is the same in the following (wrong) sample:

#include <stdio.h>

int main()
{
  int cond = 2;
  switch (cond) {
    case 1:
      printf("case 1\n");
      int i = 1;
    case 2:
      printf("case 2: %d\n", i);
  } /* Here ends the life-time of i */
  return 0;
}

Again, I compiled and tested in ideone.com. Output was case 2: 0. Ouch again!

Solution

To mimic multi-branching correctly, the following things are necessary:

1. End each case with a break.

2. Start a scope after each colon of a case.

3. End this scope before the corresponding break.

Example again:

#include <stdio.h>

int main()
{
  int cond = 2;
  switch (cond) {
    case 0: case 1: { /* <- start scope */
      int i = 1;
      printf("case 1: %d\n", i);
    } break; /* <- end scope and jump to end of switch */
    case 2:
      printf("case 2: %d\n", i); /* i is recognized as unknown identifier */
  }
  return 0;
}

Compiled in ideone:

prog.c: In function ‘main’:
prog.c:12:34: error: ‘i’ undeclared (first use in this function)
           printf("case 2: %d\n", i); /* i is recognized as unknown identifier */
                                  ^

As the scope of variable i is limited to the range from the possible entrance (case 0: case 1:) until the possible exit (break) – no other possible code path may access it.