ncurses printw bug when embedded in double for loop, c++
I am making a simple game in c++ that outputs to the console. Im using printw for this with ncurses. To print the grid, I have a for loop as follows:
for (int j; j < height + 2; j ++){
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
}
The output of this is just one line of #'s. At first I thought maybe it had something to do with the variable height, so I replaced it with its value, 22. Same, failed result. Then I physically typed out two for loops like this:
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
for (int i; i<width+2; i++){
printw("#");
}
and I got two lines of #'s! Really weird bug. I also tried while loops, but I had the same failed result. I'm new to c++, I come from python, so I could be missing something super obvious here. Thanks in advance!
c++ ncurses
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
add a comment |
I am making a simple game in c++ that outputs to the console. Im using printw for this with ncurses. To print the grid, I have a for loop as follows:
for (int j; j < height + 2; j ++){
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
}
The output of this is just one line of #'s. At first I thought maybe it had something to do with the variable height, so I replaced it with its value, 22. Same, failed result. Then I physically typed out two for loops like this:
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
for (int i; i<width+2; i++){
printw("#");
}
and I got two lines of #'s! Really weird bug. I also tried while loops, but I had the same failed result. I'm new to c++, I come from python, so I could be missing something super obvious here. Thanks in advance!
c++ ncurses
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
On Stack Overflow, we generally don't edit "SOLVED" into questions; accepting answers automatically marks it as "solved" by changing the colour showed in question listings etc. It's fine -- that's not written in the tour -- but I'm just letting you know.
– wizzwizz4
Nov 13 '18 at 17:03
thanks. i didnt know that.
– Deejpake
Nov 13 '18 at 21:55
add a comment |
I am making a simple game in c++ that outputs to the console. Im using printw for this with ncurses. To print the grid, I have a for loop as follows:
for (int j; j < height + 2; j ++){
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
}
The output of this is just one line of #'s. At first I thought maybe it had something to do with the variable height, so I replaced it with its value, 22. Same, failed result. Then I physically typed out two for loops like this:
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
for (int i; i<width+2; i++){
printw("#");
}
and I got two lines of #'s! Really weird bug. I also tried while loops, but I had the same failed result. I'm new to c++, I come from python, so I could be missing something super obvious here. Thanks in advance!
c++ ncurses
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
I am making a simple game in c++ that outputs to the console. Im using printw for this with ncurses. To print the grid, I have a for loop as follows:
for (int j; j < height + 2; j ++){
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
}
The output of this is just one line of #'s. At first I thought maybe it had something to do with the variable height, so I replaced it with its value, 22. Same, failed result. Then I physically typed out two for loops like this:
for (int i; i<width+2; i++){
printw("#");
}
printw("n");
for (int i; i<width+2; i++){
printw("#");
}
and I got two lines of #'s! Really weird bug. I also tried while loops, but I had the same failed result. I'm new to c++, I come from python, so I could be missing something super obvious here. Thanks in advance!
c++ ncurses
c++ ncurses
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
edited Nov 13 '18 at 17:03
wizzwizz4
3,44011635
3,44011635
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
asked Aug 16 '18 at 6:00
DeejpakeDeejpake
1157
1157
On Stack Overflow, we generally don't edit "SOLVED" into questions; accepting answers automatically marks it as "solved" by changing the colour showed in question listings etc. It's fine -- that's not written in the tour -- but I'm just letting you know.
– wizzwizz4
Nov 13 '18 at 17:03
thanks. i didnt know that.
– Deejpake
Nov 13 '18 at 21:55
add a comment |
On Stack Overflow, we generally don't edit "SOLVED" into questions; accepting answers automatically marks it as "solved" by changing the colour showed in question listings etc. It's fine -- that's not written in the tour -- but I'm just letting you know.
– wizzwizz4
Nov 13 '18 at 17:03
thanks. i didnt know that.
– Deejpake
Nov 13 '18 at 21:55
On Stack Overflow, we generally don't edit "SOLVED" into questions; accepting answers automatically marks it as "solved" by changing the colour showed in question listings etc. It's fine -- that's not written in the tour -- but I'm just letting you know.
– wizzwizz4
Nov 13 '18 at 17:03
On Stack Overflow, we generally don't edit "SOLVED" into questions; accepting answers automatically marks it as "solved" by changing the colour showed in question listings etc. It's fine -- that's not written in the tour -- but I'm just letting you know.
– wizzwizz4
Nov 13 '18 at 17:03
thanks. i didnt know that.
– Deejpake
Nov 13 '18 at 21:55
thanks. i didnt know that.
– Deejpake
Nov 13 '18 at 21:55
add a comment |
2 Answers
2
active
oldest
votes
You're not initialising your variables to 0, so they could be anything! Rewrite it like this:
for (int j = 0; j < height + 2; j ++){
for (int i = 0; i<width+2; i++){
printw("#");
}
printw("n");
}
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
Thanks! That worked!
– Deejpake
Aug 16 '18 at 16:16
add a comment |
In Python, a for loop is used for iterating over a sequence (that is either a list, a tuple or a string). This is less like the for keyword in other programming language, and works more like an iterator method as found in other object-orientated programming languages.
The traditional for loop in C++ is different from Python's. (There is a version of for which is called range-based for introduced in C++11 which is similar to Python's.)
In C++, you have to initialize the variables declared in the for loop before using them, otherwise the behaviour would be unexpected.
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
Thank you! Was just a syntax error after all.
– Deejpake
Aug 16 '18 at 16:16
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You're not initialising your variables to 0, so they could be anything! Rewrite it like this:
for (int j = 0; j < height + 2; j ++){
for (int i = 0; i<width+2; i++){
printw("#");
}
printw("n");
}
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
Thanks! That worked!
– Deejpake
Aug 16 '18 at 16:16
add a comment |
You're not initialising your variables to 0, so they could be anything! Rewrite it like this:
for (int j = 0; j < height + 2; j ++){
for (int i = 0; i<width+2; i++){
printw("#");
}
printw("n");
}
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
Thanks! That worked!
– Deejpake
Aug 16 '18 at 16:16
add a comment |
You're not initialising your variables to 0, so they could be anything! Rewrite it like this:
for (int j = 0; j < height + 2; j ++){
for (int i = 0; i<width+2; i++){
printw("#");
}
printw("n");
}
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
You're not initialising your variables to 0, so they could be anything! Rewrite it like this:
for (int j = 0; j < height + 2; j ++){
for (int i = 0; i<width+2; i++){
printw("#");
}
printw("n");
}
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
answered Aug 16 '18 at 6:05
wizzwizz4wizzwizz4
3,44011635
3,44011635
Thanks! That worked!
– Deejpake
Aug 16 '18 at 16:16
add a comment |
Thanks! That worked!
– Deejpake
Aug 16 '18 at 16:16
Thanks! That worked!
– Deejpake
Aug 16 '18 at 16:16
Thanks! That worked!
– Deejpake
Aug 16 '18 at 16:16
add a comment |
In Python, a for loop is used for iterating over a sequence (that is either a list, a tuple or a string). This is less like the for keyword in other programming language, and works more like an iterator method as found in other object-orientated programming languages.
The traditional for loop in C++ is different from Python's. (There is a version of for which is called range-based for introduced in C++11 which is similar to Python's.)
In C++, you have to initialize the variables declared in the for loop before using them, otherwise the behaviour would be unexpected.
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
Thank you! Was just a syntax error after all.
– Deejpake
Aug 16 '18 at 16:16
add a comment |
In Python, a for loop is used for iterating over a sequence (that is either a list, a tuple or a string). This is less like the for keyword in other programming language, and works more like an iterator method as found in other object-orientated programming languages.
The traditional for loop in C++ is different from Python's. (There is a version of for which is called range-based for introduced in C++11 which is similar to Python's.)
In C++, you have to initialize the variables declared in the for loop before using them, otherwise the behaviour would be unexpected.
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
Thank you! Was just a syntax error after all.
– Deejpake
Aug 16 '18 at 16:16
add a comment |
In Python, a for loop is used for iterating over a sequence (that is either a list, a tuple or a string). This is less like the for keyword in other programming language, and works more like an iterator method as found in other object-orientated programming languages.
The traditional for loop in C++ is different from Python's. (There is a version of for which is called range-based for introduced in C++11 which is similar to Python's.)
In C++, you have to initialize the variables declared in the for loop before using them, otherwise the behaviour would be unexpected.
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
In Python, a for loop is used for iterating over a sequence (that is either a list, a tuple or a string). This is less like the for keyword in other programming language, and works more like an iterator method as found in other object-orientated programming languages.
The traditional for loop in C++ is different from Python's. (There is a version of for which is called range-based for introduced in C++11 which is similar to Python's.)
In C++, you have to initialize the variables declared in the for loop before using them, otherwise the behaviour would be unexpected.
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
answered Aug 16 '18 at 6:48
P.WP.W
12.6k3844
12.6k3844
Thank you! Was just a syntax error after all.
– Deejpake
Aug 16 '18 at 16:16
add a comment |
Thank you! Was just a syntax error after all.
– Deejpake
Aug 16 '18 at 16:16
Thank you! Was just a syntax error after all.
– Deejpake
Aug 16 '18 at 16:16
Thank you! Was just a syntax error after all.
– Deejpake
Aug 16 '18 at 16:16
add a comment |
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On Stack Overflow, we generally don't edit "SOLVED" into questions; accepting answers automatically marks it as "solved" by changing the colour showed in question listings etc. It's fine -- that's not written in the tour -- but I'm just letting you know.
– wizzwizz4
Nov 13 '18 at 17:03
thanks. i didnt know that.
– Deejpake
Nov 13 '18 at 21:55