Why is my null check for struct array still prints even it is null for C code?

Question

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <conio.h>
#include <windows.h> 

int TotalCI = 0;
int count = 0;
struct depend{
    char dependency[200];
};

struct intdepend{
    char interdependency[200];
};

struct infradep{    
    char name[200];
    int depcount;
    struct depend Dep[20];
    int intdepcount;
    struct intdepend IntDep[20];
};

struct infradep ci[50];

void menuModel(){
    
    int menu4;
    system("cls");
    printf("=========================================\n");
    printf("\tDependency Model\n");
    printf("=========================================\n");
    count = 0;
    for (int j=0; j < TotalCI; j++)
    {
        count++;
//      printf("%d)",count);
//      printf("%s\n",ci[j].name);
        
        for(int k=0; k <= ci[j].depcount; k++)
        {
            if(ci[j].Dep[k].dependency != 0)
            {
                printf(" %s ---> %s\n", ci[j].name, ci[j].Dep[k].dependency);
            }
        }   
        
        for(int m=0; m <= ci[j].intdepcount; m++)
        {
            if(ci[j].IntDep[m].interdependency != 0)
            {
                printf(" %s <---> %s\n", ci[j].name, ci[j].IntDep[m].interdependency);
            }
        }   
    }
}

Im trying to print out the non null value from my struc Dep[20] and struct IntDep[20]. The IF statement works but, it displays like this:

=========================================
        Dependency Model
=========================================
 Drinking Water ---> Food
 Drinking Water ---> Transport
 Drinking Water ---> 
 Drinking Water <---> Food
 Drinking Water <---> 
 Waste Water ---> Chemical
 Waste Water ---> Manufacture
 Waste Water ---> 
 Waste Water <--->

The code print extra line with null struct value, making it look weird. Can anyone teach me or help me how to fix this?

for(int k=0; k <= ci[j].depcount; k++) You may want < instead of <= here. — 001
– 001, Commented Jan 12, 2022 at 20:52
dependency is a string, not a pointer. It can never be null. — Barmar
– Barmar, Commented Jan 12, 2022 at 20:53
@JohnnyMopp Thanks man, that works. Its displaying properly now. — Mohamad Aizuddin
– Mohamad Aizuddin, Commented Jan 12, 2022 at 21:13

Barmar · Accepted Answer · 2022-01-12 20:55:37Z

1

An array can never be equal to 0. If you want to test if the string is empty, check the first character.

            if(ci[j].Dep[k].dependency[0] != '\0')

answered Jan 12, 2022 at 20:55

Barmar

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