I am a beginner in C language and encountered some problems while practicing "summing integer segments". However, I am not sure where my code went wrong and I would like to seek help. It displays an error message saying 'Only output one line'.

[Sunflowers6666]

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Question

Body

Question:
Given two integers A and B, output all integers from A to B and the sum of these numbers.
Input format:
Input two integers A and B in one line, where one is 100 ≤ A ≤ B ≤ 100, separated by a space.
Output format:
Firstly, output all integers from A to B in sequence, with each 5 digits occupying a line and each digit occupying a width of 5 characters, aligned to the right. Finally, output the sum of all numbers in the format of sum=x on a single line.

My Code:

#include <stdio.h>
int main()
{
    int A,B;
    int i=0;
    int sum=0;
    scanf("%d %d",&A,&B);
    while ( A <= B ){
        sum+=A;
        printf("%5d",A);
        A++;
        if ( i < 4){
            i++;
        }else{
            printf("\n");
            i=0;
        }
    }
    printf("\n");
    printf("Sum = %d",sum);
    return 0;
}

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[Adeel-x]

You actually did a fantastic job with this, and your core logic is 99% correct.

The error you are getting is a strict formatting issue caused by a sneaky "double newline."

In your while loop, if you print exactly 5 numbers, your else statement triggers and prints a newline (\n). However, right after your loop finishes, you have an unconditional printf("\n");. This means if your numbers fit perfectly into rows of 5, your code will print an extra, empty blank line right before the Sum = X line. Automated graders will fail your code for having that empty line!

To fix this, it is highly recommended to use the modulo operator (%) for line breaks. It checks if your current count is cleanly divisible by 5.

Here is the cleaned-up, passing version of your code:

C
#include <stdio.h>

int main() {
int A, B;
int sum = 0;
int count = 0; // Tracks how many numbers we've printed

scanf("%d %d", &A, &B);

// A for-loop is usually cleaner for counting sequences
for (int i = A; i <= B; i++) {
    printf("%5d", i);
    sum += i;
    count++;
    
    // If we have printed exactly 5 numbers, break the line
    if (count % 5 == 0) {
        printf("\n");
    }
}

// Only print a final newline if our last row wasn't a perfect multiple of 5
// This prevents the "extra blank line" bug!
if (count % 5 != 0) {
    printf("\n");
}

printf("Sum = %d", sum);

return 0;

}

Run this through your grader, and it should immediately give you the pass.

[Sunflowers6666]

Okay, I have solved the problem according to what you taught me. Thank you very much for your help!