// Rademaker Robin - Array practice in C++ Part 2 - 15/O3/2019 // [4] Multi-dimensional array with diagonal sum // ISSUES FILE - tl2br += myArray4[i][i]; ** doesn't work ** // See below #include #include // for manipulating output using namespace std; int main() { // [4] Multi-dimensional array with 3 rows and 3 columns // Array indexes [0][0], [1][1], [2][2] will be count together // which is diagonal from top-left to bottom-right. // we can also do diagonal from bottom-left to top-right // Array indexes [0][2], [1][1], [2][2] will be count together. /* top-left: top-right: [5] 2 3 5 2 [3] 4 [5] 3 4 [5] 3 2 4 [5] [2] 4 5 */ int myArray4[3][3] = {{2,2,2}, {5,5,5},{10,10,10}}; // extra row for storing diagonal results SOLVES PROBLEM // int myArray4[4][3] = {{2,2,2}, {5,5,5},{10,10,10}}; cout << "\n\n"; cout << "[4] Multi-dimensional array with diagonal sum:"; cout << "\n\n"; // count3 is used to write Row 1,2,3 int count3 = 1; // * Doesn't work with += WHY?** // int tl2br = 0; // top-left to bottom-right ** tl2br += myArray4[i][i]; int bl2tr = 0; // bottom-left to top-right ** bl2tr += myArray4[r-i][i]; // * Doesn't work ** // int tl2brA[1][1]; // top-left to bottom-right array // int bl2trA[1][1]; // bottom-left to top-right array // We use 2 for loops // LOOP for ROWS for(int i = 0; i < 3; i++){ cout << "Row " << count3 << ": "; // LOOP for COLUMNS for(int x = 0; x < 3 ; x++){ // cout.fill('0'); indicates that a 0 has to be added // to get at least 2 numbers we use setw(2) // #include is added on top for this cout.fill('0'); cout << setw(2) << myArray4[i][x] << " "; } // END LOOP for COLUMNS // new line next row // Row count cout << endl; count3++; } // END LOOP for ROWS cout << "\n"; // Now lets count up ** SOMETHING IS WRONG WITH HERE? WHAT? ** for(int i = 0; i < 3; i++){ // this SHOULD ADD up the diagonals top-left to bottom-right // ** Doesn't work, Why? ** // tl2br += myArray4[i][i]; ** doesn't work ** // tl2brA[0][0] += myArray4[i][i]; ** doesn't work ** // myArray4[3][0] += myArray4[i][i]; ** passing to an array works, check solution in other file ** tl2br = myArray4[i][i]; // like this the correct value is passed ** cout << tl2br << " "; // print to follow what happens tl2br += myArray4[i][i]; } // END LOOP cout << "\n"; int r = 2; //0,1,2 = 3 for(int i = 0; i < 3; i++){ // this SHOULD ADD up the diagonals bottom-left top-right // Doesn't work, Why? // bl2tr += myArray4[r-i][i]; ** doesn't work ** bl2tr = myArray4[r-i][i]; // like this the correct value is passed ** cout << bl2tr << " "; // print to follow what happens } // END LOOP cout << "\n\n" << "SUM Top-left to bottom-right: " << tl2br << endl << "SUM Bottom-left to Top-right " << bl2tr << "\n\n"; return 0; }

Cpp - Array practice in C++ part2 - ISSUES