Transpose a Matrix in C and C++

What is Transpose a Matrix?

A transpose maps the value at row i, column j to row j, column i.

Important points

Compile with warnings enabled and fix every warning.
Know the lifetime and type of every value.
Validate input and keep array bounds explicit.

See how it works

Press transpose to swap rows and columns. Point at a cell to see its new position and memory offset.

C and C++ code examples

C

Run code →

main.c

#include <stdio.h>
int main(void) {
    int matrix[2][3] = {{1, 2, 3}, {4, 5, 6}};
    // Visit columns first to print the transposed shape.
    for (int column = 0; column < 3; ++column) { for (int row = 0; row < 2; ++row) printf("%s%d", row ? " " : "", matrix[row][column]); puts(""); }
}

Result of running the code

1 4
2 5
3 6

C++

Run code →

main.cpp

#include <array>
#include <iostream>
int main() {
    std::array<std::array<int, 3>, 2> matrix{{{{1, 2, 3}}, {{4, 5, 6}}}};
    // Visit columns first to print the transposed shape.
    for (size_t column = 0; column < 3; ++column) { for (size_t row = 0; row < 2; ++row) std::cout << (row ? " " : "") << matrix[row][column]; std::cout << '\n'; }
}

Result of running the code

1 4
2 5
3 6

C and C++ comparison

Nested loops visit every matrix coordinate and print columns from the original matrix as rows.

C

C exposes small procedural APIs and makes representation details explicit.

C++

C++ retains the low-level model while adding safer library types and abstractions.

Practice exercises

Run both versions, then modify them to observe the different language guarantees.

Add invalid and boundary-value inputs.
Compile with -Wall -Wextra -Wpedantic.
Move reusable declarations into a header and implementation file.

Practice with a challenge

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