path: root/C/MatrixCalculator.c

/* 
 * SCROLL TO BOTTOM FOR DOCUMENTATION 
 */

#include <stdio.h>  // printf, scanf
#include <string.h> // strcspn, strtok
#include <stdlib.h> // atoi, atof

#define MAX_LINE_WIDTH 1024
#define MATRIX_NUMBER_DELIMITER " "

#define CMND_END          "end"
#define CMND_PRINT_MATRIX "print"
#define CMND_PRINT_VARS   "printv"
#define CMND_SWAP_ROWS    "swap"
#define CMND_MULT_ROW     "mult"
#define CMND_DIV_ROW      "div"
#define CMND_SUM_ROW      "sum"

/* Matrix commands */
void sumRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int swapVars, double vars[][matrixCols]);
void multRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int swapVars, double vars[][matrixCols]);
void divRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int swapVars, double vars[][matrixCols]);
void swapRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int swapVars, double vars[][matrixCols]);

/* Arrays */
void assignArrValues(int cols, double arrDest[], double arrSrc[]);
void multArrValues(int len, double arr[], double value);

/* IO */
void printMatrix(int mr, int mc, double matrix[][mc]);
void inputToMatrix(char inputBuffer[], int matrixRows, int matrixCols, double matrix[][matrixCols]);
void getInput(char inputBuffer[MAX_LINE_WIDTH]);


int main() {
	/* 
	 * Get matricies
	 */

	int rows, cols, hasVars;
	scanf("%d %d %d\n", &rows, &cols, &hasVars);

	double matrix[rows][cols];
	double vars[rows][cols];

	char inputBuffer[MAX_LINE_WIDTH];

	inputToMatrix(inputBuffer, rows, cols, matrix);

	if (hasVars)
		inputToMatrix(inputBuffer, rows, cols, vars);

	/* 
	 * Modify matricies
	 */

	printf("Commands:\n");

	char *command;
	do {
		getInput(inputBuffer);
		command = strtok(inputBuffer, MATRIX_NUMBER_DELIMITER);

		if (!strcmp(inputBuffer, CMND_SWAP_ROWS))
			swapRows(command, rows, cols, matrix, hasVars, vars);

		else if (!strcmp(inputBuffer, CMND_MULT_ROW))
			multRows(command, rows, cols, matrix, hasVars, vars);

		else if (!strcmp(inputBuffer, CMND_DIV_ROW))
			divRows(command, rows, cols, matrix, hasVars, vars);

		else if (!strcmp(inputBuffer, CMND_SUM_ROW))
			sumRows(command, rows, cols, matrix, hasVars, vars);

		else if (!strcmp(inputBuffer, CMND_PRINT_MATRIX))
			printMatrix(rows, cols, matrix);

		else if (!strcmp(inputBuffer, CMND_PRINT_VARS))
			printMatrix(rows, cols, vars);

	} while (strcmp(inputBuffer, CMND_END) != 0);

	/* 
	 * End print
	 */

	printMatrix(rows, cols, matrix);
	if (hasVars)
		printMatrix(rows, cols, vars);
}

/* 
 * Matrix commands
 */

void sumRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int sumVars, double vars[][matrixCols]) {
	/* Get input */

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	int rowSrc = atoi(command) - 1;

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	int rowDst = atoi(command) - 1;

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	double mult = atof(command);

	double tmp[matrixCols];

	/* Sum matrix rows */

	assignArrValues(matrixCols, tmp, matrix[rowSrc]);
	multArrValues(matrixCols, tmp, mult);

	for (int i = 0; i < matrixCols; i++)
		matrix[rowDst][i] += tmp[i];

	/* Sum var rows */

	if (sumVars) {
		assignArrValues(matrixCols, tmp, vars[rowSrc]);
		multArrValues(matrixCols, tmp, mult);

		for (int i = 0; i < matrixCols; i++)
			vars[rowDst][i] += tmp[i];
	}
}

void multRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int multVars, double vars[][matrixCols]) {
	/* Get input */

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	int row = atoi(command) - 1;

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	double amount = atof(command);

	/* Multiply matrix row */

	multArrValues(matrixCols, matrix[row], amount);

	/* Multiply var row */

	if (multVars)
		multArrValues(matrixCols, vars[row], amount);
}

void divRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int divVars, double vars[][matrixCols]) {
	/* Get input */

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	int row = atoi(command) - 1;

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	double amount = atof(command);

	/* Divide matrix row */

	multArrValues(matrixCols, matrix[row], 1.0/amount);

	/* Divide var row */

	if (divVars)
		multArrValues(matrixCols, vars[row], 1.0/amount);
}

void swapRows(char *command, int matrixRows, int matrixCols, double matrix[][matrixCols], int swapVars, double vars[][matrixCols]) {
	/* Get input */

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	int row1 = atoi(command) - 1;

	command = strtok(NULL, MATRIX_NUMBER_DELIMITER);
	int row2 = atoi(command) - 1;

	double tmp[matrixCols];

	/* Swap matrix rows */

	assignArrValues(matrixCols, tmp, matrix[row1]);
	assignArrValues(matrixCols, matrix[row1], matrix[row2]);
	assignArrValues(matrixCols, matrix[row2], tmp);

	/* Swap var rows */

	if (swapVars) {
		assignArrValues(matrixCols, tmp, vars[row1]);
		assignArrValues(matrixCols, vars[row1], vars[row2]);
		assignArrValues(matrixCols, vars[row2], tmp);
	}
}

/*
 * Arrays
 */

void assignArrValues(int len, double arrDest[], double arrSrc[]) {
	for (int i = 0; i < len; i++)
		arrDest[i] = arrSrc[i];
}

void multArrValues(int len, double arr[], double value) {
	for (int i = 0; i < len; i++)
		arr[i] *= value;
}

/* 
 * IO 
 */

void printMatrix(int mr, int mc, double matrix[][mc]) {
	for (int r = 0; r < mr; r++) {
		/* Left bracket */

		if (r == 0) printf("/");
		else if (r == mr - 1) printf("\\");
		else printf("|");

		/* Middle values */

		for (int c = 0; c < mc; c++)
			printf(" %.3g ", matrix[r][c]);

		/* Right bracket */

		if (r == 0) printf("\\");
		else if (r == mr - 1) printf("/");
		else printf("|");
		printf("\n");
	}
}

void inputToMatrix(char inputBuffer[], int matrixRows, int matrixCols, double matrix[][matrixCols]) {
	char *singleVal;
	for (int r = 0; r < matrixRows; r++) {
		/* Get input */

		getInput(inputBuffer);
		singleVal = strtok(inputBuffer, MATRIX_NUMBER_DELIMITER);

		/* Assign input to matrix */

		for (int c = 0; c < matrixCols; c++) {
			matrix[r][c] = atof(singleVal);

			singleVal = strtok(NULL, MATRIX_NUMBER_DELIMITER);
		}
	}
}

void getInput(char inputBuffer[MAX_LINE_WIDTH]) {
	fgets(inputBuffer, MAX_LINE_WIDTH, stdin);
	inputBuffer[strcspn(inputBuffer, "\n")] = 0; // Removes trailing \n
}

/* This is a small "calculator" for matricies. You type in the values of your matricies, then what actions to do with the rows and finally you'll get your calculated result.
 * If your matrix uses variables alongside numbers, you can use the "var" matrix, which will calculate the result for each variable separately
 *
 * All inputs must be separated by spaces!
 * First input should be three numbers: amount of rows, amount of columns and whether to use the var matrix (0 for "don't use it", anything else for "use it").
 * After that you type in the values of your matricies, each number separated by a space and each line separated by a newline.
 *
 * All rows are indexed from 1! So, if you have 3 rows, the first one is at "index" 1 (index when typing in command)
 *
 * Then you can do the commands. There are 7 different ones in total:
 * - end : ends the app (and prints the matricies)
 * - print : prints the normal matrix
 * - printv : prints the var matrix
 * - swap <srcRow> <destRow> : swaps the values between two rows
 * - mult <row> <multiplier> : multiplies a row by a given number (and saves that to the row)
 * - div <row> divisor : divides a row by a given number (and saves that to the row)
 * - sum <srcRow> <destRow> <srcMultiplier> : multiplies a row by a given number (without modifying it) and adds it to another row (sample usage: multiply first row by 1 and sum that to the 3rd row: sum 1 2 1)

 * Sample usage (what gets typed and what gets outputted):
 * (Stuff that are typed in by the use start with ** in the examples)
 *
 * I. No vars
 *
 * Matrix in task looks like:
 * /  1 -1 0 -1 \
 * |  2 -4 2 10 |
 * \ -1  1 1  5 /
 *
** 3 4 0
** 1 -1 0 -1
** 2 -4 2 10
** -1 1 1 5
 * Commands:
** div 2 2
** swap 1 2
** sum 1 2 -1
** print
 * / 1  -2  1  5 \
 * | 0  1  -1  -6 |
 * \ -1  1  1  5 /
** sum 1 3 1
** sum 2 3 1
** end
 * / 1  -2  1  5 \
 * | 0  1  -1  -6 |
 * \ 0  0  1  4 /
 *
 * (I'm too lazy to implement a system for aligning the numbers properly)
 *
 * I. With vars
 *
 * Matrix in task looks like:
 * /  1 -1   0   -1 \
 * |  2 -4 2*p 10*q |
 * \ -1  1   1    5 /
 *
** 3 4 1
** 1 -1 0 -1
** 2 -4 2 10
** -1 1 1 5
** 0 0 0 0
** 0 0 1 1
** 0 0 0 0
 * Commands:
** div 2 2
** swap 1 2
** sum 1 2 -1
** print
 * / 1  -2  1  5 \
 * | 0  1  -1  -6 |
 * \ -1  1  1  5 /
** printv
 * / 0  0  0.5  0.5 \
 * | 0  0  -0.5  -0.5 |
 * \ 0  0  0  0 /
** sum 1 3 1
** sum 2 3 1
** end
 * / 1  -2  1  5 \
 * | 0  1  -1  -6 |
 * \ 0  0  1  4 /
 * / 0  0  0.5  0.5 \
 * | 0  0  -0.5  -0.5 |
 * \ 0  0  0  0 /
 *
 * You'll have to add the first value from normal matrix to the value of var matrix * variable
 * So, the proper result looks something like:
 * / 1  -2   1+0.5*p   5+0.5*q \
 * | 0   1  -1-0.5*p  -6-0.5*q |
 * \ 0   0         1         4 /
 * (I'm too lazy to implement this type of printing) 
 */