C PROGRAMMING PROGRAM • POINTERS & DYNAMIC MEMORY

Calculate the Difference Between Two Array Pointers

Learn how to calculate the difference between two array pointers using a clear C program.

Beginnerptrdiff_tPointer subtractionArray positions

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

Element distance = 3

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>
#include <stddef.h>

int main(void)
{
    int values[] = {10, 20, 30, 40, 50};
    int *first = &values[1];
    int *second = &values[4];
    ptrdiff_t distance = second - first;
    printf("Element distance = %td\n", distance);
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Element distance = 3

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Subtract pointers into the same array to obtain their distance measured in elements.
Display the computed result.

Subtract pointers into the same array to obtain their distance measured in elements.

EFFICIENCY

Time and space complexity

Time complexity

O(1)

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.