Finding the sum of digits of a number in C is a classic programming exercise that teaches digit extraction using the modulo operator. You extract each digit by taking n % 10, add it to a running total, then divide n by 10 to drop the last digit. Repeat until no digits remain. This technique …
Two matrices are equal if and only if they have the same dimensions (same number of rows and same number of columns) and every corresponding pair of elements is equal: A[i][j] == B[i][j] for all i, j. If the dimensions differ, equality is impossible. This program checks both conditions. The original had void main(), exit(1) …
Selection Sort works by repeatedly finding the minimum element from the unsorted portion of the array and placing it at the beginning. After each pass, the sorted portion grows by one element from the left. It always performs exactly O(n²) comparisons regardless of input order — unlike Bubble or Insertion Sort, there is no early …
This program reads a sentence and swaps the case of every letter — uppercase becomes lowercase, lowercase becomes uppercase. Digits, spaces, and punctuation are left unchanged. The <ctype.h> functions isupper(), islower(), toupper(), and tolower() make this clean and portable across all ASCII and extended character sets. The original post used conio.h, void main(), a broken …
A palindrome is a word, sentence, or sequence that reads the same forward and backward — ignoring differences in capitalization for word-level palindromes. Examples: “racecar”, “GADAG”, “level”, “9009”. The most efficient check uses a two-pointer approach: one pointer starts at the left end, one at the right, and they advance toward each other until they …
The transpose of a matrix is formed by flipping it over its main diagonal — rows become columns and columns become rows. If the original matrix is of order M×N, its transpose is of order N×M, where element A[i][j] becomes B[j][i]. Matrix A (3×2): Transpose B (2×3): 1 2 1 3 5 3 4 → …