As others have said, the issue is the store to the memory location in the array: x[i][j]. Here’s a bit of insight why: You have a 2-dimensional array, but memory in the computer is inherently 1-dimensional. So while you imagine your array like this: 0,0 | 0,1 | 0,2 | 0,3 —-+—–+—–+—- 1,0 | 1,1 … Read more
You can achieve this like following : map<string, int>::iterator it; for (it = symbolTable.begin(); it != symbolTable.end(); it++) { std::cout << it->first // string (key) << ‘:’ << it->second // string’s value << std::endl; } With C++11 ( and onwards ), for (auto const& x : symbolTable) { std::cout << x.first // string (key) << … Read more
Patrick Smacchia blogged about this last month, with the following conclusions: for loops on List are a bit more than 2 times cheaper than foreach loops on List. Looping on array is around 2 times cheaper than looping on List. As a consequence, looping on array using for is 5 times cheaper than looping on … Read more
This lists all the files (and only the files) in the current directory and its subdirectories recursively: for /r %i in (*) do echo %i Also if you run that command in a batch file you need to double the % signs. for /r %%i in (*) do echo %%i (thanks @agnul)
The better practice is to use for-each. Besides violating the Keep It Simple, Stupid principle, the new-fangled forEach() has at least the following deficiencies: Can’t use non-final variables. So, code like the following can’t be turned into a forEach lambda: Object prev = null; for(Object curr : list) { if( prev != null ) foo(prev, … Read more
for…in iterates over property names, not values, and does so in an unspecified order (yes, even after ES6). You shouldn’t use it to iterate over arrays. For them, there’s ES5’s forEach method that passes both the value and the index to the function you give it: var myArray = [123, 15, 187, 32]; myArray.forEach(function (value, … Read more
A common construct is to run a loop until something is found and then to break out of the loop. The problem is that if I break out of the loop or the loop ends I need to determine which case happened. One method is to create a flag or store variable that will let … Read more
A couple of notes first: when you use Data/data1.txt as an argument, should it really be /Data/data1.txt (with a leading slash)? Also, should the outer loop scan only for .txt files, or all files in /Data? Here’s an answer, assuming /Data/data1.txt and .txt files only: #!/bin/bash for filename in /Data/*.txt; do for ((i=0; i<=3; i++)); … Read more
.values() You can call the values() method on your enum. for (Direction dir : Direction.values()) { // do what you want } This values() method is implicitly declared by the compiler. So it is not listed on Enum doc.
for in loops over enumerable property names of an object. for of (new in ES6) does use an object-specific iterator and loops over the values generated by that. In your example, the array iterator does yield all the values in the array (ignoring non-index properties).