C PROGRAMMING PROGRAM • LOOPS & NUMBER PROBLEMS

Print the Fibonacci Series

Learn how to print the fibonacci series using a clear C program.

BeginnerSequenceLoopState update

PROBLEM UNDERSTANDING

Input and expected output

Sample input

Sample output

0 1 1 2 3 5 8 13

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int terms;
    unsigned long long first = 0, second = 1;

    printf("Enter number of terms: ");
    scanf("%d", &terms);
    if (terms < 1 || terms > 94) {
        printf("Use a term count from 1 to 94.\n");
        return 0;
    }
    for (int index = 0; index < terms; index++) {
        printf("%llu%c", first, index == terms - 1 ? '\n' : ' ');
        unsigned long long next = first + second;
        first = second;
        second = next;
    }
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

0 1 1 2 3 5 8 13

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Print the current term, then shift the pair forward using their sum.
Display the computed result.

Print the current term, then shift the pair forward using their sum.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

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Use the correct format specifier for every variable.

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Initialize variables before using their values.

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Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.