Wrong result adding elements of array

Question

    #include<stdio.h>
    int main()
    { 
    int get()
    {
      int n;
      int sum=0;
      int  i;
      int a[i];
      printf("enter the value of n");
      scanf("%d",&n);
      if(n==5)
      {
         printf("ok");
      }
      else
      {
        printf("not ok dont enter next value re run the program");
      }
      printf("enter the values of array");
     for(int i=1;i<=n;i++)
     {
      scanf("%d",&a[i]);
     }
     printf("the sum of array is ");
     for(int i=1;i<=n;i++)
     {
      sum=sum+a[i];
      printf("%d\n",sum);
     }
     }
     get(); 
     return 0;  
     }

but when i write below code it doesnot give the output as i am expecting

    #include<stdio.h>
    int main()
    { 
    int get()
    {
      int n;
      int sum=0;
      int  i;
      int a[i];
      printf("enter the value of n");
      scanf("%d",&n);
      if(n==5)
      {
         printf("ok");
      }
      else
      {
        printf("not ok dont enter next value re run the program");
      }
      printf("enter the values of array");
     for(int i=1;i<=n;i++)
     {
      scanf("%d",&a[i]);
     }
     printf("enter the values of array");
     for(int i=1;i<=n;i++)
     {
      printf("%d",a[i]);
     }
     printf("the sum of array is ");
     for(int i=1;i<=n;i++)
     {
      sum=sum+a[i];
      printf("%d\n",sum);
     }
     }
     get(); 
     return 0;  
     }

it does not give the expected output please help

Problem

You are given an array A consisting of N integers.

Task

Print the sum of the elements in the array.

Note: Some of the integers may be quite large.

Input Format

The first line contains a single integer N denoting the size of the array.
The next line contains space-separated integers denoting the elements of the array.

Output format

Print a single value representing the sum of the elements in the array.

Constraints

1<=N<=10

0<=a[i]<=10^10

Sample Input

5
1000000001 1000000002 1000000003 1000000004 1000000005

Sample Output

5000000015

         #include <cmath>
         #include <cstdio>
         #include <vector>
         #include <iostream>
         #include <algorithm>
         using namespace std;
         typedef long long int list;


        int main() {
        /* Enter your code here. Read input from STDIN. Print output to 
        STDOUT */   
        list n,sum=0;
        cin>>n;
        while(n--)
        {
        list a;
        cin>>a;
        sum+=a;
        }
        cout<<sum;
        return 0;
        }

this program gave the correct solution.its quite complex to understand but it works according to the expectations.

        #include <stdio.h>
     int main() 
     {  
     int i, n, value;
     long long sum = 0;
     scanf("%d", &n);
     for (i = 0; i < n; i++)
     {
     scanf("%d",&value);
     sum =sum + value;
     }
     printf("%lld", sum);
     return 0;
     }

this c program is accepted by machine which is much simpler form except how variable value is acting as an array without [] these symbols

Answer 1

There are multiple problems in your code:

• it is very difficult to read because the presentation is bad. You should use indentation consistently, 4 characters is considered preferable.

• you cannot define local functions in Standard C. Define get() before the main() function or write the code directly inside the main() function.

• defining the array int a[i]; with i uninitialized has undefined behavior. You could define the array as int a[n]; after you read the number of elements n, but there is actually no need for an array: you can compute the sum as you read the values.

• you should use type long long for sum to help avoid overflow if the sum exceeds INT_MAX.

• The more complex program is written in C++, which is a different language, originally inspired by the C language, but quite different today. The code uses type long long via a very confusing list typedef. The while(n--) is risky: the loop will keep reading values if the user enters a negative value and there is no error handling for invalid input.

Here is a modified version:

#include <stdio.h>

int main() {  
    int i, n, value;
    long long sum = 0;

    printf("enter the value of n: ");
    if (scanf("%d", &n) != 1) {
        printf("invalid input, re run the program\n");
        return 1;
    }
    printf("enter the values of array: ");
    for (i = 0; i < n; i++) {
        if (scanf("%d", &value) != 1) {
            printf("invalid input, breaking from the loop\n");
            break;
        }
        sum += value;
    }
    printf("the sum of array is %lld\n", sum);
    return 0;  
}