Loop issue, stop prematurely - c++

Question

I have a homework assignment which I feel I am close to getting right. The assignment is as follows:
Banks loan money to each other. In tough economic times, If a bank goes bankrupt it may not be able to pay back the loan. A bank's total assets is its current balance plus its loans to other banks. Figure 8.1 ( attached image ) is a diagram tat shows five banks. The banks' current balances are: 25, 125, 175, 75 and 181 million dollars, respectively. The directed edge from node 1 to node 2 indicates that bank 1 loans 40 mill to bank 2.
If a banks total asset is under a certain limit, the bank is considered unsafe. If a bank is unsafe, the money it borrowed cannot be returned to the lender and the lender cannot count the loan in its total assets. Consequently, the Lender may also be unsafe.
Write a program to find all unsafe banks. Your program reads the input as follows. It first reads two integers, n and limit, where n indicates the number of banks and limit is the minimum assets for keeping a bank safe. It then reads n lines that describe the information for n banks with id from 0 to n-1. The first number in the line is the bank's balance. The second number indicates the number of that borrowed money from the bank, and the rest are pairs of two numbers. Each pair describes a borrower. The first number is the banks id and the second number is how much it borrowed. Assume that the maximum number of banks is 100. For example, the input for the five banks is as follows ( the limit is 201)
5 201
25 2 1 100.5 4 320.5
125 2 2 40 3 85
175 2 0 125 3 75
75 1 0 125
181 1 2 125
The total assets of bank 3 is 75 plus 125 which is under 201 so the bank is unsafe. After bank 3 is unsafe the total assets of bank 1 becomes 125 + 40 and is now also unsafe. The output should be "Unsafe banks are 3 1"
This is my current solution to the problem. I can't figure out how to get it to find all the unsafe banks. Just the first one. I have it set to take static input for testing. I have the working user input code ready to go if I can just get it to work properly.
#include <iostream>
using namespace std;
int main()
{
const int SIZE = 100;
double balance[SIZE];
double loan[SIZE][SIZE];
int nobanks;
int limit;
int i = 0;
int j = 0;
int k = 0;
int noborrowers;
double assets[SIZE];
bool isSafe[SIZE];
bool newunsafefound = true;
cout << "Enter number of banks and the limit:" << endl;
// Set all of the data
nobanks = 5;
limit = 201;
balance[0] = 25.0;
balance[1] = 125.0;
balance[2] = 175.0;
balance[3] = 75.0;
balance[4] = 181.0;
loan[0][1] = 100.5;
loan[0][4] = 320.5;
loan[1][2] = 40.0;
loan[1][3] = 85.0;
loan[2][0] = 125.0;
loan[2][3] = 75.0;
loan[3][0] = 125.0;
loan[4][2] = 125.0;
// Set array to all true values
for(i = 0; i < nobanks; i++)
{
isSafe[i] = true ;
}
cout << "Unsafe banks are: ";
i=0;
while(isSafe[i] == true)
{
newunsafefound=false;
i=0;
do
{
assets[i] = balance[i]; //Set assets to balance
for (j = 0; j < nobanks; j++) // Check if a bank has loans and add them to assets
{
if (loan[i][j] >= 0)
assets[i] += loan[i][j];
}
if (assets[i] < limit) // Check to see if current bank meets limit
{
isSafe[i] = false; // Set bank to not safe if limit not met
newunsafefound = true;
cout << i << " " ; //Display the bank that is unsafe and a space for the next bank
k=0;
for (k = 0; k < nobanks; k++)
{
loan[i][k] = 0; //Set banks loans to 0 if unsafe.
k++;
}
}
i++;
} while(i < nobanks);
}
return (0);
}
What am I doing wrong?

Answer 1

You have to explicitly initialize the loan array, so the elements you aren't using don't have arbitrary values:
double loan[SIZE][SIZE] = {{0}};
Also loan[i][k] = 0; means that you are zeroing the loan the bank i has given to the bank k, but what you want is to zero any money that the bank i has borrowed to the bank k.
And there is a problem:
in the exit condition of your outer loop (it would only exit if the last bank (nobank-1) was unsafe),
in the handling of newunsafefound which doesn't do what the variable name suggests.

Answer 2

for (k = 0; k < nobanks; k++)
{
loan[i][k] = 0; //Set banks loans to 0 if unsafe.
k++;
}
That extra increment for k looks very suspicious ;)

Answer 3

// Astrid Giraldo
public static void main (String[] args) {
Scanner input = new Scanner(System.in);
int n; // number of banks
double limit; // Minimum total assets for keeping a bank safe.
System.out.println("Enter number of banks: ");
n = input.nextInt();
System.out.println("Enter minimum total assets to be a safe bank: ");
limit = input.nextDouble();
double[][] borrowers = new double[n][n];
double[] balance = new double[n];
int numBorrowers;
for (int i = 0; i < borrowers.length; i++) {
System.out.println("Enter the bank's balance");
balance[i] = input.nextDouble();
System.out.println("Enter number of borrowers from this bank");
numBorrowers = input.nextInt();
for (int j = 0; j < numBorrowers; j++) {
System.out.println("Enter borrower bank id and the amount borrowed: ");
borrowers[i][input.nextInt()] = input.nextDouble();
}
}
markUnsafeBanks(borrowers,balance, limit);
displayUnsafeBanks(borrowers, balance, limit);
}
public static double analizeUnsafeBanks(double[][] borrowers, double[] balance, int bankId) {
double sum = balance[bankId];
for (int i = 0; i < borrowers.length; i++) {
sum += borrowers[bankId][i];
}
return sum;
}
public static void setLoanToZero(double[][] borrowers, double[] balance, int unsafeBankId, double limit) {
for (int i = 0; i < borrowers.length; i++) {
if (borrowers[i][unsafeBankId] > 0) {
borrowers[i][unsafeBankId] = 0;
if ( unsafeBankId > i && analizeUnsafeBanks(borrowers, balance, i) < limit) {
setLoanToZero(borrowers, balance, i, limit);
}
}
}
}
public static void markUnsafeBanks(double[][] borrowers, double[] balance, double limit) {
for (int i = 0; i < borrowers.length; i++) {
if (analizeUnsafeBanks(borrowers, balance, i) < limit) {
setLoanToZero(borrowers, balance, i, limit);
}
}
}
public static void displayUnsafeBanks(double[][] borrowers, double[] balance, double limit){
for (int i = 0; i < borrowers.length; i++) {
double assets = analizeUnsafeBanks(borrowers,balance,i);
if ( assets < limit) {
System.out.println("Bank " + i + " is unsafe. It assets are " + assets);
}
}
}