I used a for loop to generate a list of strings, and I've been trying to make them print horizontally instead of vertically.
Currently:
the list is printed vertically, up to 10.
Goal: To have the list printed horizontally.
Code for reference:
#include <iostream>
using namespace std;
int main()
{
int x = 10;
int y, z = 0;
int result;
for (z = 1; z <= x; z++)
{
cout << '\n';
for (y = 1; y <= z; y++)
{
result = z * y;
cout << z << " * " << y << " = " << result << '\n';
}
cout << '\n';
}
}
For the first block of number (1x1 .. 5x5), here's something similar to your expected output.
for (int x = 1; x <=5 ; x++) {
for (int y = 1; y <= 5; y++) {
if (y < x) {
cout << " ";
}
else {
cout << setw(3) << y << " x " << setw(4) << x << " = " << setw(4) << x * y << " ";
}
}
cout << endl;
}
Prints out this:
1 x 1 = 1 2 x 1 = 2 3 x 1 = 3 4 x 1 = 4 5 x 1 = 5
2 x 2 = 4 3 x 2 = 6 4 x 2 = 8 5 x 2 = 10
3 x 3 = 9 4 x 3 = 12 5 x 3 = 15
4 x 4 = 16 5 x 4 = 20
5 x 5 = 25
I'll leave it as an exercise for extending this to another set of rows for the 6 through 10 times tables.
Related
I would like to store the smallest value of compute_evaluation_function in current_best_eval, and the corresponding vector that gives that smallest value in ILS_best_p, I've succeeded with the current_best_eval, but can't seem to get it for the ILS_best_p even though they're under the same if statement.
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <algorithm>
#include <cassert>
#include <ctime>
#include <cmath>
using namespace std;
long int **read_matrix(ifstream &input, long int n);
double ran01(long int *idum);
long int *generate_random_vector(long int n);
unsigned long int compute_evaluation_function(long int n);
void first_2_opt_symmetric (long int n);
void swap(long int pos_1, long int pos_2, long int *);
void perturbation(long int pert_size);
long int *p;//the vector generated from generate_random_vector()
long int **d;//one of the matrices read from file
long int **f;//one of the matrices read from file
long int n;
long int actual_solution_value;
long int new_eval;
long int current_eval;
#define IA 16807
#define IM 2147483647
#define AM (1.0/IM)
#define IQ 127773
#define IR 2836
int main()
{
string name;
long int optimum;
ifstream infile;
long int initial_eval;
long int *ILS_best_p;
long int new_vs_current;
new_vs_current = INT_MAX;
long int current_best_eval;
current_best_eval = INT_MAX;
long int new_current_eval;
long int best_eval;
long int improvement;
long int i;
long int j;
infile.open("nug12.dat");
infile >> name;
cout << "Name: " << name << "\n";
infile >> n;
cout << "Rows and Columns: " << n << "\n";
infile >> optimum;
cout << "Optimum solution: " << optimum << "\n";
d=read_matrix(infile, n);
f=read_matrix(infile, n);
cout << endl;
p=generate_random_vector(n);
compute_evaluation_function(n);
cout << endl;
first_2_opt_symmetric (n);
cout << endl;
initial_eval = compute_evaluation_function(n);
cout << endl << endl;
for (i = 0; i < 500; i++) //ILS loop
{
if (new_eval < current_eval)
{
new_vs_current = new_eval;
cout << "iteration 1st = " << i+1 << " " << endl;
}
else if (current_eval < new_eval)
{
new_vs_current = current_eval;
cout << "iteration 2nd = " << i+1 << " " << endl;
}
cout << "iteration = " << i+1 << " " << endl;
cout << " Vector before perturbation = ";
for (j = 0; j < n; j++)
{
cout << p[j] << " ";
}
cout << endl << endl;
cout << endl << "current best eval = " << current_best_eval << endl;
perturbation(3);
cout << endl << endl;
cout << endl << "current best eval = " << current_best_eval << endl;
cout << " Vector after perturbation = ";
for (j = 0; j < n; j++)
{
cout << p[j] << " ";
}
cout << endl << endl;
cout << endl << "current best eval = " << current_best_eval << endl;
first_2_opt_symmetric (n);
new_current_eval = compute_evaluation_function(n);
cout << endl << "current best eval = " << current_best_eval << endl;
cout << endl;
cout << " Vector after local search = ";
for (j = 0; j < n; j++)
{
cout << p[j] << " ";
}
cout << endl << endl;
cout << endl << "current best eval = " << current_best_eval << endl;
cout << " Vector p = ";
for (j = 0; j < n; j++)
{
cout << p[j] << " ";
}
cout << endl << endl;
if (new_current_eval < current_best_eval)
{
new_eval = new_current_eval;
cout << "iteration 3rd = " << i+1 << " " << endl;
}
else if (current_best_eval <= new_current_eval)
{
new_eval = current_best_eval;
cout << "iteration 4th = " << i+1 << " " << endl;
}
if (new_eval < new_vs_current)
{
current_best_eval = new_eval;
cout << "iteration 5th = " << i+1 << " " << endl;
ILS_best_p = p;
}
else if (new_vs_current < new_eval)
{
current_best_eval = new_vs_current;
cout << "iteration 6th = " << i+1 << " " << endl;
ILS_best_p = p;
}
cout << endl << "current best eval = " << current_best_eval << endl;
}
cout << endl << "current best eval = " << current_best_eval << endl;
cout << "ILS best vector = ";
for (i = 0; i < n; i++)
{
cout << ILS_best_p[i] << " ";
}
return 0;
}
long int **read_matrix(ifstream &input, long int n)
{
/*
FUNCTION: read instance matrices
INPUT: instance file name, instance size
OUTPUT: d-matrix and f-matrix
(SIDE)EFFECTS: none
COMMENTS: read the distance matrix and flow matrix
*/
long int i, j;
long int **matrix = new long int *[n];
for (i = 0; i < n; i++)
{
matrix[i] = new long int[n];
for (j = 0; j < n; j++)
{
if( !(input >> matrix[i][j]) )
{
cerr << "Error reading at " << i << j << endl;
exit(1);
}
}
}
return matrix;
}
double ran01(long int *idum)
{
/*
FUNCTION: returns a pseudo-random number
INPUT: a pointer to the seed variable
OUTPUT: a pseudo-random number uniformly distributed in [0,1]
(SIDE)EFFECTS: changes the value of seed
*/
long k;
double ans;
k =(*idum)/IQ;
*idum = IA * (*idum - k * IQ) - IR * k;
if (*idum < 0 )
{
*idum += IM;
}
ans = AM * (*idum);
return ans;
}
long int *generate_random_vector(long int n)
{
/*
FUNCTION: generates a random vector
INPUT: vector dimension
OUTPUT: returns pointer to vector, free memory when vector is not needed anymore
(SIDE)EFFECTS: none
*/
long int i, j, help;
long int *v;
srand(time(0));
long int seed=rand();
v = new long int[ n ];
for ( i = 0 ; i < n; i++ )
{
v[i] = i;
}
for ( i = 0 ; i < n-1 ; i++)
{
j = (long int) ( ran01( &seed ) * (n - i));
assert( i + j < n );
help = v[i];
v[i] = v[i+j];
v[i+j] = help;
}
return v;
}
unsigned long int compute_evaluation_function(long int n)
{
/*
FUNCTION: compute evaluation function
INPUT: pointer to solution
OUTPUT: evaluation function
(SIDE)EFFECTS: none
COMMENTS: none
*/
long int i, j;
unsigned long obj_f_value;
obj_f_value = 0;
for(i = 0; i < n; i++)
{
for(j = 0; j < n; j++)
{
obj_f_value += d[i][j] * f[p[i]][p[j]];
}
}
cout << obj_f_value;
return obj_f_value;
}
void first_2_opt_symmetric (long int n)
{
/*
FUNCTION: first improvement 2-opt local search for symmetric instances
INPUT: pointer to some initial assignment
OUTPUT: none
(SIDE)EFFECTS: initial assignment is locally optimized, dlb is used to increase the search speed, the dlb value is changed to false if item change it's location during perturbation
COMMENT: neighborhood is scanned in random order, use of register for faster computation
*/
long int improvement = 1;
long int improve_item = 0;
long int u, v, i, j, k;
long int tmp;
long int *x;
improvement = 1;
x = generate_random_vector(n);
while (improvement)
{
improvement = 0;
for ( i = 0 ; i < n ; i++ )
{
u = x[i];
improve_item = 0;
for ( j = 0 ; j < n ; j++ )
{
v = x[j];
if (u == v)
continue;
tmp = 0;
for ( k = 0 ; k < n ; k++ )
{
if ( (k != u) && (k != v) )
{
tmp += (d[u][k] - d[v][k]) * (f[p[v]][p[k]] - f[p[u]][p[k]]);
}
}
if (tmp < 0)
{
improvement = 1;
improve_item = 1;
swap (u, v, p);
}
}
}
}
delete []x;
}
void swap(long int pos_1, long int pos_2, long int *p)
{
/*
FUNCTION: swap position of two items in a vector
INPUT: position 1, position 2, pointer to vector
OUTPUT: none
(SIDE)EFFECTS: none
COMMENTS: none
*/
long int tmp;
tmp = p[pos_1];
p[pos_1] = p[pos_2];
p[pos_2] = tmp;
}
void perturbation(long int pert_size)
{
/*
FUNCTION: apply random perturbation
INPUT: pointer to solution, perturbation scheme, perturbation strength, change in perturbation, end perturbation size
OUTPUT: none
(SIDE)EFFECTS: new solution formed from old solution
COMMENTS: none
*/
long int hold_value[n]; //allocate memory for items to be chosen in move/*
int chosen[pert_size]; //*allocate temporary memory to determine items to be moved */*
long int i;
for(i = 0; i < n; i++)
{
hold_value[i] = p[i]; //initialize hold_value with the same value from local search/*
}
int j = n - 1;
int rand_number;
int rand_no;
for(i = 1; i <= pert_size; i++)
{
rand_number = rand();
rand_no = rand_number % j; //choose random number from 1 to size - 1/
chosen[i - 1] = rand_no + i; //copy the value to chosen[i]
j--;
}
long int temp;
for(i = 0; i < pert_size; i++)
{
temp = chosen[i];
swap(i, temp, hold_value); //swap chosen[i] and hold_value[i]; n first item in hold_value[i] is the index array that will be included in perturbation/
}
long int temp1;
long int temp2;
temp1 = p[hold_value[1]];//
temp2 = p[hold_value[0]];
for(i = 0; i < pert_size - 1; i++)
{
p[hold_value[i + 1]] = temp2;
temp2 = temp1;
temp1 = p[hold_value[i + 2]];
}
p[hold_value[0]] = temp2;
actual_solution_value = compute_evaluation_function(n);
new_eval = actual_solution_value;
current_eval = new_eval;
}
This is the file I read from:
Nug12
12
578
0 1 2 3 1 2 3 4 2 3 4 5
1 0 1 2 2 1 2 3 3 2 3 4
2 1 0 1 3 2 1 2 4 3 2 3
3 2 1 0 4 3 2 1 5 4 3 2
1 2 3 4 0 1 2 3 1 2 3 4
2 1 2 3 1 0 1 2 2 1 2 3
3 2 1 2 2 1 0 1 3 2 1 2
4 3 2 1 3 2 1 0 4 3 2 1
2 3 4 5 1 2 3 4 0 1 2 3
3 2 3 4 2 1 2 3 1 0 1 2
4 3 2 3 3 2 1 2 2 1 0 1
5 4 3 2 4 3 2 1 3 2 1 0
0 5 2 4 1 0 0 6 2 1 1 1
5 0 3 0 2 2 2 0 4 5 0 0
2 3 0 0 0 0 0 5 5 2 2 2
4 0 0 0 5 2 2 10 0 0 5 5
1 2 0 5 0 10 0 0 0 5 1 1
0 2 0 2 10 0 5 1 1 5 4 0
0 2 0 2 0 5 0 10 5 2 3 3
6 0 5 10 0 1 10 0 0 0 5 0
2 4 5 0 0 1 5 0 0 0 10 10
1 5 2 0 5 5 2 0 0 0 5 0
1 0 2 5 1 4 3 5 10 5 0 2
1 0 2 5 1 0 3 0 10 0 2 0
Please explain the execution of the program such that why it will generate such specific outputs.
The output is
6 10 20
6 10 8
2 2 14
My guess would have to be that it is due to the IN, OUT, INOUT parameters but I am not really understanding it
#include <iostream>
using namespace std;
void sunny(int&, int);
void cloudy(int, int&);
int temp;
int main()
{
int num1 = 6;
int num2 = 10;
temp = 20;
cout << num1 << " " << num2 << " " << temp << endl;
sunny(num1, num2);
cout << num1 << " " << num2 << " " << temp << endl;
cloudy(num1, num2);
cout << num1 << " " << num2 << " " << temp << endl;
}
void sunny(int& a, int b)
{
int w;
temp = (a + b) / 2;
w = a / temp;
b = a + w;
a = temp - b;
}
void cloudy(int u, int& v)
{
temp = 2 * u + v;
v = u;
u = v - temp;
}
Actually the output is:
6 10 20
2 10 8
2 2 14
We can see the steps like this:
Sunny call:
temp = (6 + 10)/2 = 8
w = 6/8 = 0 //This is because w is declared int, and int(6/8) = 0
b = 6 + 0 = 10
a = 8 - 6 = 2
Therefore num1 is now 2, because of the reference argument, and temp is changed to 8 because its global
Cloudy call:
temp = 2 * 2 + 10 = 14
v = 2
u = 2 - 14 = -12 //This variable is doing nothing
Therefore num2 is now 2 for same reason as before and temp is 14
The program should ask a user to enter a number and it forms a triangle using the numbers between 1 and the given number. I came up with a code:
cout << "Enter a number: ";
cin >> rows;
for (int y = rows; y > 0; --y)
{
for (int x = 1; x <= y; x++)
{
cout << x << " ";
}
cout << endl;
}
And I would get:
Enter a number: (user inputs number, lets say 7)
1 2 3 4 5 6 7
1 2 3 4 5 6
1 2 3 4 5
1 2 3 4
1 2 3
1 2
1
but I can't seem to get it to:
7 6 5 4 3 2 1
* 6 5 4 3 2 1
* * 5 4 3 2 1
* * * 4 3 2 1
* * * * 3 2 1
* * * * * 2 1
* * * * * * 1
without it going completely wrong. Any possible tips?
int rows;
cout << "Enter a number: ";
cin >> rows;
for (int y = rows; y > 0; --y)
{
for (int x = rows; x > 0; x--)
{
if (x <= y) cout << x << " ";
else cout << "* ";
}
cout << endl;
}
This is how you could do it:
cout << "Enter a number: ";
cin >> rows;
for (int y = rows; y > 0; --y)
{
for(int h = rows-y; h>0; --h){
cout<<"*";
}
for (int x = y; x >= 1; --x)
{
cout << x << " ";
}
cout << endl;
}
#include <iostream> // подключаем библиотеку ввода-вывода
#include <cmath> // подключаем библиотеку математических функций
using namespace std;
int main()
{
float a, x, y = 0; // объявление переменных
cout << "Enter a variable: ";
cin >> a; // запрос на ввод a
cout << "Enter x variable: ";
cin >> x; // запрос на ввод x
cout << "a = " << a << ", x = " << x; // вывод a и x
y = (pow(x, 3) + sqrt(1 + pow(x, 3))) / (a + exp(x)); // формула расчета
cout << y;
}
Enter a variable: 6
Enter x variable: 7
a = 6, x = 70.327894
I can't understand why x == 70, when it must be 7. Also I don't know why cout << y; doesn't work. If I delete y = ... and cout << y, x display correctly.
I think, that it's my fault, because I'm new in C++ and don't know syntax well.
You're simply printing everything on the same line, you can either:
Print it after your two first result:
cout << "a = " << a << ", x = " << x; // вывод a и x
y = (pow(x, 3) + sqrt(1 + pow(x, 3))) / (a + exp(x)); // формула расчета
cout << ", y = " << y;
Output:
Enter a variable: 6
Enter x variable: 7
a = 6, x = 7, y = 0.327894
Or print y on another line
cout << "a = " << a << ", x = " << x << "\n"; // returns to another line
y = (pow(x, 3) + sqrt(1 + pow(x, 3))) / (a + exp(x)); // формула расчета
cout << "y = " << y;
Output:
Enter a variable: 6
Enter x variable: 7
a = 6, x = 7
y = 0.327894
a = 6, x = 70.327894
this doesn't mean x =70.327894.
x is 7 and the result y is 0.327894
you need to carefully print to the terminal, use << endl; and add some more labels so you can easily recognize the output of the math calculation...
bottomline: your rocket formula is working fine and you need to take another coffee... :)
i'm a beginner in C++ and i'm doing this example code of assignment operators. I don't know what i'm doing wrong here.
#include <iostream>
using namespace std;
int main()
{
int x = 200; int y = 100;
x += y; cout << x << endl; //x += y; // x = x + y, x = 200 + 100, output 300.
x -= y; cout << x << endl; //x -= y; // x = x - y, x = 200 - 100, output 100.
x /= y; cout << x << endl; //x /= y; // x = x / y, x = 200 / 100, output 2.
x %= y; cout << x << endl; //x % y; // x = % y, x = 200 % 100, output 0.
return 0;
}
i'm getting the results for
x -= y = 200
x /= y = 2
x %= y = 2
when its suppose to be
x -= y = 100
x /= y = 2
x %= y = 0
its actually adding up the previous results. How do i stop the code from adding the result to the next line? Thanks!
As you mentioned in your comments in your code, the result of x += y is equivalent to x = x + y, which means the value of x will change. So it is no surprise that the new value of x, 300, is used in the next mathematical assignment.
If you want to avoid that, consider saving the result of x + y to another variable.
int x = 200;
int y = 100;
int x_addition = x + y;
std::cout << x_addition << std::endl;
Or, if its only usage is in displaying the result of the addition, do it all in one line.
int x = 200;
int y = 100;
std::cout << x + y << std::endl;
When x and y are variables and U is an operation x U= y is equivalent to:
x = x U y;
which means the original variable is being modified and assigned with the result.
You code is equivalent to:
x = x + y;
cout << x << endl; // x is now 300
x = x - y;
cout << x << endl; // x is now 200
x = x / y;
cout << x << endl; // x is now 2
x = x % y;
cout << x << endl; // x is now 2
If you want not to change x you want can save x in a temporary variable or just print the result:
int x = 200;
int y = 100;
cout << x - y << endl; // x unchanged
cout << x + y << endl; // x unchanged
cout << x / y << endl; // x unchanged
cout << x * y << endl; // x unchanged
Or:
int x = 200;
int x = 100;
int result = x + y;
cout << result << endl;
result = x - y;
cout << x << endl;
result = x / y;
cout << result << endl;
result = x % y;
cout << result << endl;
Note: since the = operator returns the value after the assignment cout << x += y << end can compile and print the assigned value.
Every time you are doing assignment like x += y;, it changing the value of x.
x += y;
is equivalent to
x = x + y;
Which means assignment. Value of x is changing. It's now 300. Same thing happening for latter assignments too.
Note: if you don't want to change the value of x and y, better do the assignments in other variable.
int x = 200, y = 100, t;
t = x + y; cout << t << endl;
t = x - y; cout << t << endl;
t = x * y; cout << t << endl;
t = (int) x / y; cout << t << endl;
You are expecting the original value of x and y to be kept forever, but it isn't. Assignments like x += y; or x = x + y; change the value of the variables (in this case x, that is, the one on the left side of the equal sign). The previous value is overwritten and therefore lost.
If you don't want to change the original values, you have to either assign the result to other variables (for example, one called temp, that you can overwrite every time), or you don't assign it at all, and you simply send to cout the result of the calculation.
As an example with a temp variable:
int x = 200; int y = 100; int temp;
temp = x + y; cout << temp << endl; //temp = x + y, temp = 200 + 100, output 300.
temp = x - y; cout << temp << endl; //temp = x - y, temp = 200 - 100, output 100.
Or, doing away with variables entirely:
cout << x + y << endl; // 200 + 100, output 300
cout << x - y << endl; // 200 - 100, output 100
Another way to see that the variables are overwritten (well, in this case it's only x) is to declare them as const:
const int x = 200; const int y = 100;
The program won't compile, because it tries to change constant variables.
Try resetting x back to 200 after each assignment. Like this:
#include <iostream>
using namespace std;
int main()
{
int x = 200; int y = 100;
x += y; cout << x << endl;
x = 200;
x /= y; cout << x << endl;
x = 200;
x %= y; cout << x << endl;
return 0;
}
You are using the accumulation operators so you're changing the value of 'x'.
x += y; // x = 200 + 100 = 300
x -= y; // x = 300 - 100 = 200
x /= y; // x = 200 / 100 = 2
x %= y; // x = 2 % 100 = 2
Instead you could do:
int x = 200;
int y = 100;
cout << x + y << endl;
cout << x - y << endl;
cout << x / y << endl;
cout << x % y << endl;
Or:
int x = 200;
int y = 100;
int result;
result = x + y;
cout << result << endl;
result = x - y;
cout << result << endl;
result = x / y;
cout << result << endl;
result = x % y;
cout << result << endl;
You are not counting on Addition operations value
x=200,y=100;
x+=y;//x=200+100=300,x=300,y=100
x-=y;//x=300-100=200,x=200,y=100
Here you are forgetting that there is ADDITION OPERATION before subtraction