C++ in Visual Studio 2017, can't input variables which are in loop

Question

I'm solving some simple problem, but I have a problem, I can only input variables N, M and P, I can't input variables tempX and tempY which are in loop, here is the code:

#include <iostream>
#include <vector>
#include <minmax.h>

using namespace std;

typedef unsigned long long ull;

int main() {
ull n, m, p;
cin >> n >> m >> p;

vector<vector<unsigned short> > field;
field.resize(n);

for (ull i = 0; i < m; i++)
    for (ull j = 0; j < m; j++)
        field[i].push_back(1);



for (ull i = 0; i < p; i++) {
    ull tempX, tempY;
    cin >> tempX >> tempY;
    field[tempX][tempY] = 0;
}

for (ull i = 1; i < n; i++)
    for (ull j = 1; j < m; j++)
        if (field[i - 1][j - 1] != 0 && field[i][j] != 0)
            field[i][j] = min(field[i - 1][j], field[i][j - 1]) + 1;

ull maxLength = 0;
for (ull i = 0; i < n; i++)
    for (ull j = 0; j < m; j++)
        maxLength = max(maxLength, field[i][j]);

cout << maxLength << endl;

return 0;
}

Btw. I had problems with printing simple text with cout, there was no problem in code but something is preventing printing simple text like "Hello world", is that connected in any way with this problem?

What do you mean by "can't input variables in loops"? Also the title is not very descriptive of the problem. — Sami Kuhmonen, Feb 15 '17 at 15:39
Please explain also what it means. You get an error? Values don't appear? What you are trying to input and what exactly happens. — Sami Kuhmonen, Feb 15 '17 at 15:42
Here is [The Definitive C++ Book Guide and List](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). — , Feb 15 '17 at 15:43
I input N, M and P, and program just ends, i have tried with system("pause") at the end but that just prints text "Press any key to continue..." and that doesn't help — Đorđe Milanović, Feb 15 '17 at 15:44
Looks like it crashes on the `field[i].push_back(1);`. I think you're using the wrong limit in that outer `for` loop. — Fred Larson, Feb 15 '17 at 15:45
You'll have problems if `m` is greater than `n`. Probably a typo. — molbdnilo, Feb 15 '17 at 15:46
Debugger. Use the Debugger. The Debugger can show you variable values at each statement. Did I say to use the Debugger? — Thomas Matthews, Feb 15 '17 at 15:49
To set all values of vector to be 1, give field[0][0], field[1][1]....field[n-1][m-1] values of 1 — Đorđe Milanović, Feb 15 '17 at 15:50
Fred Larson and Thomas Matthews, I don't know how to use debugger and how to see variable values — Đorđe Milanović, Feb 15 '17 at 15:54
Then learn to use a debugger. It is more important then knowing all the ins and outs of a programming language. It helps you in solving these problems. Really: first learn to use a debugger, then start writing your own code. — JHBonarius, Feb 15 '17 at 15:57
`#include ` is wrong. Use `#include ` to get `std::min` and `std::max`. Don't use `using namespace std;`. And if you ever get problems due to ``'s stupid `min` and `max` macros, make Visual Studio define `NOMINMAX` when it invokes Visual C++ on the *.cpp file. — Christian Hackl, Feb 15 '17 at 17:13

score 0 · Accepted Answer · answered Feb 15 '17 at 16:04

0

vector<vector<unsigned short> > field;
field.resize(n);

for (ull i = 0; i < m; i++)
    for (ull j = 0; j < m; j++)
        field[i].push_back(1);

there's a mistake already there. m instead of n

for (ull i = 0; i < n; i++)

You should properly name your variables. n is not a good name. numberOfRows or rowCount or matrixDimension1 could be better.

By the way, use stl.

for (ull i = 0; i < n; i++)
    for (ull j = 0; j < m; j++)
        field[i].push_back(1);

could be

for (ull i = 0; i < field.size(); i++)
    field[i].resize(m, 1);

And it could be more simple. Just look at examples online.

answered Feb 15 '17 at 16:04

JHBonarius

10,824
3
22
41

Mistake with m instead of n was a typo, but – Đorđe Milanović Feb 15 '17 at 16:08
Thank you, I have corrected mistake and now it is working, i haven't know that I can do "field[i].resize(m, 1)" this but now it is helpful. – Đorđe Milanović Feb 15 '17 at 16:11

C++ in Visual Studio 2017, can't input variables which are in loop

1 Answers1