Modularization problem (basic)

[DoEds]

I wonder what's the final values of the variables "a, b and c" after this program... It is in pseudocode....

start
       a = 2
       b = 4
       c = 10

       while c > 6
               perform changeBandC()
       endwhile
     
       if a = 2 then
               perform changeA()
       endif
      
       if c = 10 then
               perform changeA()
       else
               perform changeBandC()
       endif
       
       print a, b, c

stop


changeBandC()
       b = b + 1
       c = c - 1
return

changeA()
       a = a + 1;
       b = b - 1;
return

I tried to code to it...But nothing is printed...
I'll post it to ask you people what's wrong with my codes?

Here's my program...

#include <stdio.h>

int changeBandC(int,int);
int changeA(int,int);

int main()
{
    int a = 2;
    int b = 4;
    int c = 10;
    
    while (c > 6)
    {
          changeBandC(b,c);
    }
    if (a == 2)
          changeA(a,b);
    if (c == 10)
          changeA(a,b);
    else
          changeBandC(b,c);

    printf("%d,%d,%d",a,b,c);
    
    getchar();
    getchar();
    
}

int changeBandC(int b,int c)
{
    int changeBandC = 0;
    b = b + 1;
    c = c - 1;
    
    return changeBandC;
}
int changeA(int a,int b)
{
    int changeA = 0;
    a = a + 1;
    b = b - 1;
 
    return changeA;
}

I hope you could help me with this...
Thanks in advance...

[Aia]

Passing values on a function is done by making a copy of it, which means the original is not modified.

int changeBandC(int b,int c)
{
    int changeBandC = 0; /* This is wrong here delete it */
    b = b + 1; /*the work is done in b which  is a copy of the original b on main */
    c = c - 1; /* c is a copy of the original c in main */
    
    return changeBandC; /* it has not purpose here, it can only return one value and I ask you which value you think is returning? */
}

Here's how you change the value of an original variable in main

#include <stdio.h>

int change(int source);

int main(void)
{
    int changeling = 1; /* lets give it a value that we know */

    /* Notice the way the value produced by the function is returned */
    changeling = change(changeling);

    /* What's in variable changeling now? */
    printf("Variable hold: \"%d\"\n", changeling);
    return 0;
}

int change(int source)
{
    source = source + 1;
    return source;
}