//=========================================== // CodeName : Square generator using for loop // Done for : Randeep Singh // By : Babak Sheykhan // Created : Nov 10, 2017 // Modified : Nov 10, 2017 // // Input tip: Enter 1 or more integer as your // input and a character to end it. // Example: // // 5 // 10 // x // // Then submit. //=========================================== #include using std::cout; using std::cin; using std::endl; int main() { int n = 0; ////////////////////////////////////// // How the following while loop works? // With respect to my previous explanation on // [www.sololearn.com/Discuss/844740/] // this loop will continue to ask for input as long as // you enter an integer AND your integer to be in the // specific range [1 to 20]. // In order to ends your execution you'd either feed the // input with a non-integer value OR a number outside the // range OR hitting Ctrl + D on Linux-based OS/ Ctrl + Z on // Windows machine. while (cout << "Size of square is (1 to 20):\n" && cin >> n && n >= 1 && n <= 20) { ///////////////////////////////////////////////////// // Your main question lies inside these two for guys. // So, How do they work exactly? // Let me explain it in an algorithmic way. // // For example n = 4, so we are gonna have a 4 * 4 square in output. // Following trace table illustrates each step of 2 for loops thoroughly. // As you see, i and j represents the outer and inner for loop steps, respectively. // When outer loop increase one step, inner loop executes the whole range between // 0 and 3 (i < 4) inclusively. // // # i j output //----|-------|-------|----------- // 1 | 0 | 0 | * // 2 | | 1 | ** // 3 | | 2 | *** // 4 | | 3 | **** <- first row done //----|-------|-------|----------- // 5 | 1 | 0 | * // 6 | | 1 | ** // 7 | | 2 | *** // 8 | | 3 | **** <- second row done //----|-------|-------|----------- // 9 | 2 | 0 | * // 10 | | 1 | ** // 11 | | 2 | *** // 12 | | 3 | **** <- third row done //----|-------|-------|----------- // 13 | 3 | 0 | * // 14 | | 1 | ** // 15 | | 2 | *** // 16 | | 3 | **** <- forth row done //----|-------|-------|----------- for (int i = 0; i < n; ++i) { for (int j = 0; j < n; ++j) cout << "*"; ////////////////////////////////////////////////// // This statement breaks the line after completion // of each row. cout << endl; } } }

[Tut]@RandeepSingh_forLoopPattern