C program is stuck while running it

Question

Ok so i made a program in c that is asking the user to choose 1 of 4 stages he would like to play in. After the user chooses the stage, the program is generating a secret code that built out of 4 chars and its between 1-6 (for example- 3516). But i wanted to make the chars non-duplicated, so there will be no 2 numbers the same (for example- 1642 its good but 6632 its bad code). After i made a few "if"s in my code and i ran it, it just stacked. This is my code:

#include <stdio.h>
#include <stdlib.h>

int getStages();
int randCode();

int main()
{
    getStage();

    system("PAUSE");
}

int getStage()
{

    int choice= 0;

    printf("What stage would you like to choose? Choose Wisely: ");
    scanf("%d", &choice);

    randCode();
}

int randCode()
{
    srand(time(NULL));

    int randFirst= rand() % 6 + 1;
    int randSecond= rand() % 6 + 1;
    int randThird= rand() % 6 + 1;
    int randFourth= rand() % 6 + 1;

     while(randFirst = (randSecond || randThird || randFourth))
     {
         int randFirst= rand() % 6 + 1;
     }

     while(randSecond = (randFirst || randThird || randFourth))
     {
         int randSecond= rand() % 6 + 1;
     }

     while(randThird = (randFirst || randSecond || randFourth))
     {
         int randThird= rand() % 6 + 1;
     }

     while(randFourth = (randFirst || randSecond || randThird))
     {
         int randFourth= rand() % 6 + 1;
     }

    char firstNumber= randFirst;
    char secondNumber= randSecond;
    char thirdNumber= randThird;
    char fourthNumber= randFourth;

    printf("%d %d %d %d\n", firstNumber, secondNumber, thirdNumber, fourthNumber);


}

Use a debugger and provide information where it is stuck (or solve yourself). — too honest for this site, Jan 08 '16 at 09:23
You are using `%d` to print the `char` which is wrong you should use `%c` — Gopi, Jan 08 '16 at 09:23
@Gopi: While you are formally right, a `char` will be passed as an `int` for variadic arguments and `%d` does take an `int`. OP likely wants to use the `char` variables not as characters but integers. — too honest for this site, Jan 08 '16 at 09:24
I think you need to check out [The Definitive C Book Guide and List](http://stackoverflow.com/questions/562303/the-definitive-c-book-guide-and-list), and find a good beginners book or tutorial. — Some programmer dude, Jan 08 '16 at 09:32
All of the rand variables are greater than zero, so the loops can never end. — rghome, Jan 08 '16 at 09:53
Sounds like a school-university problem. Try reading C first. Your question is pointless to me. — JmRag, Jan 08 '16 at 09:58

rootkea · Answer 1 · 2016-01-08T09:43:22.087

= is not same as ==.
a = b means assign b to a. a == b means check whether a equals to b or not.
To check an variable for equivalence to more than one variable form expression as

((foo == var1) || (foo == var2) || (foo == var3) ...)

while(randFirst = (randSecond || randThird || randFourth))

This is causing the problem.

What this expression does is to assign 1 to randFirst if any of randSecond, randThird or randFourth is non-zero. Otherwise assign 0 to randFirst (When all other remaining 3 variables are 0)

And then if randFirst got assigned 1 (which is most probable) then, while is always true since in loop too randFirst gets assigned to non-zero number (1 to 6). So an infinite loop.

Similar thing happens with all other remaining while loops.

Instead use:

while((randFirst == randSecond) || (randFirst == randThird) || (randFirst == randFourth))

in all subsequent while expressions.

score 0 · Answer 2 · answered Jan 08 '16 at 09:26

You declare the variables randFirst to randFourth locally inside the loops, shadowing the other variables by the same name you have. The values you assign within the loop are only assigned to these loop-local variables.

This of course have an effect on the loop conditions (once you fix them) as the loop condition will use the function-local variables. If you enter a loop, that loop will be infinite.

score 0 · Answer 3 · answered Jan 08 '16 at 09:29

0

The condition in the while looop is always true and hence it goes infinite time because (a==b) is comparision where as a=b is assignment which is always true.

answered Jan 08 '16 at 09:29

madhusudhan samantray

31
3

Unless the value of `b` is zero. – Some programmer dude Jan 08 '16 at 09:30

C program is stuck while running it

3 Answers3