It's not a HW assignment.
Reason I asked which should I call is that i've tried calling them but they don't seem to work...even if I allow file to be called in main and allow it to just print a simple statement it still doesn't work...only fupdate and menu works properly...

I need help with this program-work-jpg

Before this program I wrote the solution to an actual problem and I used a function with it and it worked correctly:

Code:
#include<stdio.h>#include<stdlib.h>
int next(int),n;
int main(){
    printf("Enter a Number: \t");
    scanf("%d",&n);
    getchar();
    int x = next(n);
    printf("Result: \t\t%d",x);
    getchar();
    return 0;
}
int next(int a){
    int x = 1;
if( (a>=0) && (a<=10000) ){    
    if(a>=0 && a<10){
        return a+1;
    }else if(a>=10 && a<=98){
        while(x=1){
            a++;
            int b=a/10;
            int c=a%10;
            if(a!=b){
                return a;
                break;
            }
        }
    }else if( (a>=987) && (a<=9876) ){
        while(x=1){
            a++;
            int w = a/1000;
            int x = (a/100)%10;
            int y = (a%100)/10;
            int z = a%10;
            if( (w!=z) && (x!=y) && (w!=x) && (y!=z) && (w!=y) && (x!=z) ){
                return a;
                break; 
            }
        }
    }else if( (a>9876) && (a<=10000) ){
        while(x=1){
            a++;
            int b = a/10000;
            int c = (a/1000)%10;
            int d = (a%1000)/100;
            int e = (a%100)/10;
            int f = a%10;
            if( (b!=c) && (b!=d) && (b!=e) && (b!=f) && (c!=d) && (c!=e) && (c!=f) && (d!=e) && (d!=f) && (e!=f) ){
                return a;
                break;
            }
        }
    }else if( (a>98) && (a<=987) ){
        while(x=1){
            a++;
            int b = a/100;
            int c = (a%100)/10;
            int d = a%10;
            if( (b!=d) && (b!=c) && (c!=d) ){
                return a;
                break;    
                    }
                }
            }
        }else{
            printf("Number out of range");
            sleep(1000);
            exit(0);
        }
    }