# Spanning matrices in c++

• Comp Sci
1. Show the evolution/reduction of the system of a 128x128 matrix with a random seed of (1.0) and
with the filling probability of 0.8. Save as a square matrix in a text file(*.txt) that has tab delimited
columns and uses newline as row terminator. Save each iteration as a seperate file with the iteration
number as its filename

3. #include<iostream>
#include<fstream>
#include<time.h>

using namespace std;

int main()
{
srand(1.0);
float P1, P0, P;
int c = 128;
int array [c][c];
for(int i=0;i<c;i++)
{
for(int j=0;j<c;j++)
{
P1 = float((rand()%100)*0.01);
P0 = 0.2;
if (P1>P0)
{
P = 1;
}
else
{
P = 0;
}
array [j] = P;
}
}
ofstream out;
out.open ("try1.txt");
for(int i=0;i<c;i++)
{
for(int j=0;j<c;j++)
{
out<<array[j]<<"\t";
}
out << "\n";
}
system("pause");
return 0;
}

I was able to generate a 128x128 matrix with filling probability 0.8 but I don't know how to show the reduction of the spanning matrix.

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nvn
Homework Helper
This is a guess, but maybe it means, replace your line for(int j=0;j<c;j++)out<<array[j]<<"\t";, in the above post, with something like the following.

Code:
n1=0;
for(int j=0;j<c;j++){
if(array[i][j]==1)n1=n1+1;else{
if(n1>0)out<<n1<<"\t";
out<<"0";
if(j<c-1)out<<"\t";
n1=0;
}
}
if(n1>0)out<<n1;
out<<"\n";