C PROGRAMMING PROGRAM • FUNCTIONS, PREPROCESSOR & COMMAND LINE

Add Values Using a Variadic Function

Learn how to add values using a variadic function using a clear C program.

Advancedstdarg.hVariable argumentsva_list

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

Sum = 66

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>
#include <stdarg.h>

int sum_values(int count, ...)
{
    va_list arguments;
    va_start(arguments, count);
    int sum = 0;
    for (int index = 0; index < count; index++) sum += va_arg(arguments, int);
    va_end(arguments);
    return sum;
}

int main(void)
{
    printf("Sum = %d\n", sum_values(5, 4, 8, 15, 16, 23));
    return 0;
}

CURRENT STEP

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EXPECTED OUTPUT FOR THE SAMPLE

Sum = 66

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Receive a count followed by that many integer arguments and visit each with va_arg.
Display the computed result.

Receive a count followed by that many integer arguments and visit each with va_arg.

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.