matrix from a file input with commas in the file - c++

Question

so my problem is that i have to read from a file that looks like this
input_M1
1,2
9,5
4,1
input_M2
3,2,6,1
4,1,7,8
of course I have to omit the "input_1" and "input_1", and i was able to do that and separate each matrix by itself in a string like this :
1,2
9,5
4,1
and this :
3,2,6.1
4,1,7,8
I was trying to make a dynamic array, i got the rows, with this
while(getline(ss,str1)){
row++;
}
and it prints the number of rows. However, when I do that for the columns :
while(getline(ss,str1,',')){
colmn++;
}
and when I print it out nothing appears.
and here is my whole code :
ifstream inFile;
inFile.open("c:\\Games\\crap.txt");
if (inFile.is_open()){
cout << "File successfully opened" << endl;
}
else{
cout << "Error opening file" << endl;
}
string sMain,sCutOut,firstMatrix,secondMatrix;
int counter = 1;
while(getline(inFile,sMain)){
sCutOut+=(sMain+'\n');
}
//cout << sCutOut << endl;
sCutOut = sCutOut.substr( sCutOut.find("1")+1,sCutOut.length() );
//cout << sCutOut << endl;
firstMatrix = sCutOut.substr( 0,sCutOut.find("input_M2") );
//cout << firstMatrix << endl;
secondMatrix = sCutOut.substr( sCutOut.find("_")+3,sCutOut.length() );
//cout << secondMatrix << endl;
istringstream ss (firstMatrix);
istringstream sn (secondMatrix);
string str1,str2,str3;
int row=0,colmn=0;
while(getline(ss,str1,'\n')){
//cout << str1 << '\n';
row++;
//cout << row << " ";
}
while(getline(ss,str2,',')){
cout << str2 << '\n';
colmn++;
cout << colmn << " ";
}
also, i get this when I try to print out the (firstMatrix) with out the new line I get this :
1,29,54,1

Answer 1

I used C++11 Regular expression library and I applied a simple regular expression to strip off the input_M? lines.
// under g++ 4.8.1 compile:
// $ g++ apply_regex.cpp -std=c++11 -lboost_regex -o apply_regex
#include <fstream>
#include <iostream>
// #include <regex> not implemented yet in g++ 4.8.1 (c++11 standard)
#include <boost/regex.hpp> // using boost libraries
using namespace std;
using boost::regex;
using boost::regex_replace;
int main() {
ifstream inFile;
inFile.open("crap.txt");
if (inFile.is_open()) {
cout << "File successfully opened" << endl;
}
else {
cout << "Error opening file" << endl;
}
string sMain, sCutOut;
while(getline(inFile,sMain)) {
sCutOut+=(sMain+'\n');
}
inFile.close();
cout << "Read lines from crap.txt" << endl;
cout << sCutOut;
// regular expression checks from input_M1 or input_M2 etc..
regex txt_regex("input_M[1-9]+");
string result = regex_replace(sCutOut, txt_regex, "");
cout << "After applying regular expression \"input_M[1-9]+\":" << endl;
cout << result;
return 0;
}
The result of the above code is:
$ ./apply_regex
File successfully opened
Read lines from crap.txt
input_M1
1,2
9,5
4,1
input_M2
3,2,6,1
4,1,7,8
After applying regular expression "input_M[1-9]+":
1,2
9,5
4,1
3,2,6,1
4,1,7,8

Answer 2

Update : i made the matrix into one line and then made them delimited with commas and that is it !
#include<iostream>
#include<fstream>
#include<string>
#include<string.h>
#include<sstream>
#include<vector>
#include<string>
#include<stdlib.h> using namespace std;
int main() {
cout << "Hello! today i'm gonna help you to multiply 2 matrices." << endl;
cout << "But first, we need to discuss the format of the file" << endl;
cout << "help me with the format so i can help you to multiply !" << endl;
cout << "this is how i like the format of the file to be : " << endl;
cout << "--------------------------------" << endl;
cout << "input_M1" << endl;
cout << "number,number," << endl;
cout << "number,number" << endl;
cout << "input_M2" << endl;
cout << "number,number," << endl;
cout << "number,number," << endl;
cout << "--------------------------------" << endl;
cout << "make sure that you put the comma at the end of each line to indicate the end of the line of the matrices [not the input_M1 or input_M2], Have fun !" << endl << endl;
string fileDirct = ""; string fileName = "";
cout << "Now, Enter the file directory, with 2 backslashs, i.e : 'C:\\\\program files'" << endl; cin >> fileDirct; cout << "and Enter the file name, followed by the file type, i.e : 'testData.txt'" << endl; cin >> fileName;
string file = fileDirct+"\\"+fileName; fileDirct = fileDirct.c_str(); ifstream infile;
infile.open(file.c_str());
//ifstream infile( "c:\\Games\\crap.txt");
string sLiner,sStoring,firstMatrix,secondMatrix,sTemp1,sTemp2;
while(infile){
getline( infile, sLiner );
sStoring+=(sLiner+'\n');
}
//cout << sStoring;
sStoring = sStoring.substr( sStoring.find("_")+3,sStoring.length() );
//cout << sStoring;
firstMatrix = sStoring.substr(0,sStoring.find("i"));
//cout << firstMatrix;
secondMatrix = sStoring.substr(sStoring.find("_")+3,sStoring.length());
//cout << secondMatrix;
istringstream ssMtrx1(firstMatrix);
istringstream ssMtrx2(secondMatrix);
istringstream ss(firstMatrix);
istringstream ssk(secondMatrix);
ssMtrx1 >> sTemp1;
istringstream ssR_C1(sTemp1);
int colmn=0;
while(getline(ssR_C1,sTemp2,',')){
colmn++;
}
//cout << colmn;
if (colmn > 6 ){
cout << "the matrix has more than 6 columns";
}
sTemp1.clear();
int row=0;
while(getline(ssMtrx1,sTemp1)){
row++;
}
//cout << row;
if (row > 6 ){
cout << "the matrix has more than 6 rows";
}
//--------------------------------------------------------------------------------
sTemp1.clear();
ssMtrx2 >> sTemp1;
istringstream ssR_C2(sTemp1);
int colmn2=0;
while(getline(ssR_C2,sTemp2,',')){
colmn2++;
}
//cout << colmn2;
if (colmn2 > 6 ){
cout << "the matrix has more than 6 columns";
}
sTemp1.clear();
int row2=0;
while(getline(ssMtrx2,sTemp1)){
row2++;
}
row2 = row2-1;
//cout << row2;
if (row2 > 6 ){
cout << "the matrix has more than 6 rows";
}
//=========================================================================
int** Mtrx1Arry = new int*[row];
for(int i = 0; i < row; ++i){
Mtrx1Arry[i] = new int[colmn];
}
int** Mtrx2Arry = new int*[row2];
for(int i = 0; i < row2; ++i){
Mtrx2Arry[i] = new int[colmn2];
}
sTemp1.clear();
sTemp2.clear();
while(getline(ss,sTemp1,'\n')){
sTemp2+=sTemp1;
}
//cout << sTemp2;
istringstream ss1(sTemp2);
sTemp1.clear();
for(int i = 0; i < row;i++){
for(int j = 0; j < colmn;j++){
getline(ss1,sTemp1,',');
Mtrx1Arry[i][j]=atoi(sTemp1.c_str());
}
}
for(int i = 0; i < row;i++){
for(int j = 0; j < colmn;j++){
//cout << Mtrx1Arry[i][j] << " ";
}
}
//-------------------------------------------------------------
sTemp1.clear();
sTemp2.clear();
while(getline(ssk,sTemp1,'\n')){
sTemp2+=sTemp1;
}
//cout << sTemp2;
istringstream ss2(sTemp2);
sTemp1.clear();
for(int i = 0; i < row2;i++){
for(int j = 0; j < colmn2;j++){
getline(ss2,sTemp1,',');
Mtrx2Arry[i][j]=atoi(sTemp1.c_str());
}
}
for(int i = 0; i < row2;i++){
for(int j = 0; j < colmn2;j++){
//cout << Mtrx2Arry[i][j] << " ";;
}
}
//=============================================================================
// mtrx1[x][y] and mtrx2[z][y] : y has to == z // while the values are under 6
if( (colmn <= 6) && (colmn2 <= 6) && (row <= 6) && (row2 <= 6)){
if (colmn==row2){
cout << "the two matrices can be multiplied " << endl;
cout << "the new matrix will be : " << row << " x " <<colmn2 << endl;
int** MtrxRsltArry = new int*[row];
for(int i = 0; i < row; ++i){
MtrxRsltArry[i] = new int[colmn2];
}
for(int i = 0; i < row;i++){
for(int j = 0; j < colmn2;j++){
MtrxRsltArry[i][j]=0;
for(int k=0; k < colmn; k++){
MtrxRsltArry[i][j]=MtrxRsltArry[i][j]+(Mtrx1Arry[i][k]*Mtrx2Arry[k][j]);
}
}
}
for(int i = 0; i < row;i++){
//cout << endl;
for(int j = 0; j < colmn2;j++){
//cout << MtrxRsltArry[i][j] << ",";;
}
}
// cout << endl;
ofstream outFile;
string cat = fileDirct+"\\result.txt";
outFile.open(cat.c_str());
cout << "the result.txt has been created at : " << fileDirct << endl;
outFile << "result_M";
for(int i = 0; i < row;i++){
outFile << endl;
for(int j = 0; j < colmn2;j++){
outFile << MtrxRsltArry[i][j] << ",";
}
}
}
else{
cout << "the two matrices can not be multiplied ";
}
}
for(int i = 0; i < colmn; ++i) {
delete [] Mtrx1Arry[i];
}
delete [] Mtrx1Arry;
for(int i = 0; i < colmn2; ++i) {
delete [] Mtrx2Arry[i];
}
delete [] Mtrx2Arry;
return 0; }