i'm trying to perform a program that prints string correctly from it's middle
the problem to me is that strange behavior to me that at certain line it agrees to print string only char by char and refuses to return it to be printed in the main function
here is my code :
string unscramble(string line)
{
string temp;
int i,j;
int len=line.size();
i=len/2-1;
j=0;
do{
if(i<0)
i=len-1;
temp[j]=line[i];
cout << temp[j];
j++;
i--;
}while(i!=(len/2)-1);
return temp;
}
Your issue is in the assignment to temp. You'll also hit an issue if the string length is even. Do it this way instead:
string unscramble(string line)
{
string temp;
int i, j;
int len = line.size();
int factor = len / 2 - 1;
if(len % 2 == 1)
factor = len / 2;
i = factor;
j = 0;
do
{
if(i < 0)
i = len - 1;
temp += line[i];
j++;
i--;
}
while(i != factor);
return temp;
}
Example input: RUT OWT SNEH HCNERF EERHTEGDIRTRAP A DNA SEVODELT
Output: THREE FRENCH HENS TWO TURTLEDOVES AND A PARTRIDGE
Related
Just learning c++. The following function is my attempt to reverse a string (doesn't work and I don't know why). Thank you for spotting my stupidity.
#include <iostream>
using namespace std;
string r(string s)
{
int len = s.length();
for (int i = 0; i < len; i++)
{
char temp = s[i];
s[i] = s[len - i];
s[len - i] = temp;
}
return s;
}
int main()
{
cout << r("ASTRING");
}
It changes first letter of the string to ' ' and outputs STRING
Another simple way:
string r(string s)
{
int len = s.length();
string temp;
for (int i = len - 1; i > -1; i--)
{
temp.push_back(s[i]);
}
s = temp;
return s; // or return temp;
}
Firstly, string.length() returns length with '\0' which mean end of string, so you need to delete 1.
Secondly, you don't travel whole string, you should stop at the middle, i/2 will just do this whatever the length is.
finally :
string r(string s)
{
int len = s.length() - 1;
for (int i = 0; i < len/2; i++)
{
char temp = s[i];
s[i] = s[len - i];
s[len - i] = temp;
}
return s;
}
So my problem is bigger but I just do not know what to do with my code. I can do what I want if I use an array works just fine but we are not using arrays yet so I have no idea how to do it. So I have to take user input as a string validate that the string is 16 characters long, all of them are digits, and most importantly I have to multiply every other or even character by 2. Then if it is a double digit add the two digit (ex. 10 1+0). Oh by the way I do not know why but every time I do i%2 == 0 I get the odd numbers. Is it because i is unsigned?
for(unsigned i = 1; i < card.length(); i++){
if (i % 2 == 1){
}
else {
}
}
return sum;
}
You could use an array of strings where each string contains a number.
Go through them checking for 2 conditions:
Double the number if it is even (i.e., i % 2 == 0)
Add the digits if the number has 2 digits (i.e., string's length is 2)
Code:
#include <iostream>
#include <iterator> using namespace std;
int TOTAL_CARDS = 16;
void printCards(string msg, string *array) {
cout<<msg<<endl;
for(int i = 0; i < TOTAL_CARDS; i++) {
cout<<"array["<<i<<"]="<<array[i]<<endl;
}
cout<<"\n"<<endl; }
int main() {
string cards[TOTAL_CARDS];
// hardcoded numbers 0 up to TOTAL_CARDS for demo purposes
for(int i = 0; i < TOTAL_CARDS; i++) {
cards[i] = to_string(i);
}
printCards("Before:", cards);
for (unsigned i = 1; i < TOTAL_CARDS; i++){
// double if even
if (i % 2 == 0){
cards[i] = to_string(stoi(cards[i]) * 2);
}
// add digits if double digit number
if (cards[i].length() == 2) {
// get each digit
string currentNum = cards[i];
int firstDigit = currentNum[0] - '0'; // char - '0' gives int
int secondDigit = currentNum[1] - '0';
// do sum and put in array
int sum = firstDigit + secondDigit;
cards[i] = to_string(sum);
}
}
printCards("After:", cards); }
Output:
Before:
array[0]=0
array[1]=1
array[2]=2
array[3]=3
array[4]=4
array[5]=5
array[6]=6
array[7]=7
array[8]=8
array[9]=9
array[10]=10
array[11]=11
array[12]=12
array[13]=13
array[14]=14
array[15]=15
After:
array[0]=0
array[1]=1
array[2]=4
array[3]=3
array[4]=8
array[5]=5
array[6]=3
array[7]=7
array[8]=7
array[9]=9
array[10]=2
array[11]=2
array[12]=6
array[13]=4
array[14]=10
array[15]=6
If you wanted to get user input for the numbers:
// get user to enter numbers
cout<<"Please enter "<<TOTAL_CARDS<<" numbers: "<<endl;
for(int i = 0; i < TOTAL_CARDS; i++) {
cin>>cards[i];
}
I found the answer to it. I first needed to create char variable named num. Convert the char to an int using chnum and then multiply.
for(unsigned i = 0; i < card.length(); i++){
if (i % 2 == 1){
num = card.at(i);
chnum = (num -'0');
add = chnum * 2;
if(add >= 10){
char ho = (add + '0');
string str(1,ho);
for (unsigned j = 0; j < str.length();j++){
char digi = str.at(j);
int chub = (digi - '0');
cout << digi;
//add = (chub) + (chub);
}
}
sum += add;
}
I'm trying to get the x factor of an input math expression, but it seems buggy.
Here is my code:
#include<iostream>
#include<math.h>
using namespace std;
int main(){
char a[100];
int res = 0; // final answer
int temp = 0; // factor of the x we are focused on - temporarily
int pn = 0; // power of 10 - used for converting digits to number
int conv; // used for conversion of characters to int
cout<< "Enter a: ";
cin>> a; //input expression
for(int i=0; i<100; i++){
// checking if the character is x - then get the factor
if(a[i]=='x'){
for(int j=1; j<=i+1; j++){
conv = a[i-j] - '0'; // conversion
if(conv>=0 && conv<=9){ // check if the character is a number
temp = temp + conv*pow(10, pn); // temporary factor - using power of 10 to convert digit to number
pn++; // increasing the power
}
else{
if(a[i-j]=='-'){
temp = -temp; // check if the sign is - or +
}
break;
}
if(i-j==0){
break;
}
}
res = res+temp; // adding the x factor to other ones
pn = 0;
temp = 0;
}
}
cout<< res;
return 0;
}
It doesn't work for some inputs, for example:
100x+3x gives 102 and 3x+3997x-4000x gives -1
But works for 130x and 150x!
Is there a problem with my code, or is there an easier way to do this?
I think you're not parsing the +. There may be some other problem I can't see in the original code, probably not. Here's the X-File:
int main(){
char a[100];
int res(0);
cout << "Enter a: ";
cin >> a;
for(int i = 0; i < 100; i++){
if(a[i] == 'x'){
int temp(0);
int pn(0);
for(int j = 1; j <= i; j++){
int conv = a[i - j] - '0';
if(conv >= 0 && conv <= 9){
temp += conv*pow(10, pn);
pn++;
} else if(a[i - j] == '-') {
temp = -temp;
break;
} else if(a[i - j] == '+') {
break;
} else {
// what to do...
}
}
res += temp;
}
}
cout << res;
return 0;
}
i'm writing a program called 'Zuma'. The program works like this.
Input:
ACCBA // a string make up of char from 'A' to 'Z'
5 // number of inputs
1 B // insert char 'B' to position '1' of the string
0 A // and so on...
2 B
4 C
0 A
When 3 same chars next to each other, we erase/remove/delete them from the string.
For example, when we insert char 'C' to position 2 of string 'ABCC', we got 'AB' because
'CCC' are removed from the string.
Output:
ABCCBA
AABCCBA
AABBCCBA // the process is AABBCCCBA -> AABBBA -> AAA -> -
- // if the string is empty, we output "-"
A
This is my code with string:
#include <iostream>
using namespace std;
int main()
{
int n, pos;
int k = 0;
int length = 0;
string zuma, marble; // i use string
cin >> zuma;
cin >> n;
for (int i = 0; i < n; ++i)
{
cin >> pos >> marble;
zuma.insert(pos, marble);
length = zuma.length(); // length of current string
// compare each char from pos[i] with pos[i+1] and pos[i+2]
// and then ++i until end of string
while (k != length && length >= 3)
{
if (zuma[k] == zuma[k + 1] && zuma[k] == zuma[k + 2])
{
zuma.erase(k, 3); // erase 3 same char in the string
k = 0; // set k to zero to start from pos[0] again
}
else
k++;
}
// if string is not empty
if (!zuma.empty())
{
cout << zuma << endl; // output the current char in the string
k = 0;
}
else
cout << "-" << endl;
}
return 0;
}
This is my code with char array:
#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
void append (char subject[], const char insert[], int pos) {
char buf[100] = {};
strncpy(buf, subject, pos);
int len = strlen(buf);
strcpy(buf+len, insert);
len += strlen(insert);
strcpy(buf+len, subject+pos);
strcpy(subject, buf);
}
int main()
{
int n, pos;
int k = 0;
int length = 0;
char zuma[100], marble[100];
scanf("%s", zuma);
scanf("%d", &n);
for (int i = 0; i < n; ++i)
{
scanf("%d %s", &pos, marble);
append(zuma, marble, pos); // acts like string::insert
length = strlen(zuma);
while (k != length && length >= 3)
{
if (zuma[k] == zuma[k + 1] && zuma[k] == zuma[k + 2])
{
//zuma.erase(k, 3); // need help with this part to remove 3 same chars like string::erase
k = 0;
}
else
k++;
}
if (strlen(zuma) != 0)
{
printf("%s\n", zuma);
k = 0;
}
else
printf("%s\n","-");
}
return 0;
}
My problem is how to write a function to remove 3 same chars just like what string::erase do?
Thanks for your help!!
You can use memmove to copy the remainder of the string to the position of the characters to remove. Use strlen to determine how much bytes to move. Note you cannot use strcpy because the source and destination buffers overlap.
if (zuma[k] == zuma[k + 1] && zuma[k] == zuma[k + 2])
{
int len = strlen(zuma+k+3) + 1; // +1 to copy '\0' too
memmove(zuma+k, zuma+k+3, len);
k = 0;
}
I am preparing the interview questions not for homework. There is one question about how to multiple very very long integer. Could anybody offer any source code in C++ to learn from? I am trying to reduce the gap between myself and others by learning other's solution to improve myself.
Thanks so much!
Sorry if you think this is not the right place to ask such questions.
you can use GNU Multiple Precision Arithmetic Library for C++.
If you just want an easy way to multiply huge numbers( Integers ), here you are:
#include<iostream>
#include<string>
#include<sstream>
#define SIZE 700
using namespace std;
class Bignum{
int no[SIZE];
public:
Bignum operator *(Bignum& x){ // overload the * operator
/*
34 x 46
-------
204 // these values are stored in the
136 // two dimensional array mat[][];
-------
1564 // this the value stored in "Bignum ret"
*/
Bignum ret;
int carry=0;
int mat[2*SIZE+1][2*SIZE]={0};
for(int i=SIZE-1;i>=0;i--){
for(int j=SIZE-1;j>=0;j--){
carry += no[i]*x.no[j];
if(carry < 10){
mat[i][j-(SIZE-1-i)]=carry;
carry=0;
}
else{
mat[i][j-(SIZE-1-i)]=carry%10;
carry=carry/10;
}
}
}
for(int i=1;i<SIZE+1;i++){
for(int j=SIZE-1;j>=0;j--){
carry += mat[i][j]+mat[i-1][j];
if(carry < 10){
mat[i][j]=carry;
carry=0;
}
else{
mat[i][j]=carry%10;
carry=carry/10;
}
}
}
for(int i=0;i<SIZE;i++)
ret.no[i]=mat[SIZE][i];
return ret;
}
Bignum (){
for(int i=0;i<SIZE;i++)
no[i]=0;
}
Bignum (string _no){
for(int i=0;i<SIZE;i++)
no[i]=0;
int index=SIZE-1;
for(int i=_no.length()-1;i>=0;i--,index--){
no[index]=_no[i]-'0';
}
}
void print(){
int start=0;
for(int i=0;i<SIZE;i++)
if(no[i]!=0){
start=i;
break; // find the first non zero digit. store the index in start.
}
for(int i=start;i<SIZE;i++) // print the number starting from start till the end of array.
cout<<no[i];
cout<<endl;
return;
}
};
int main(){
Bignum n1("100122354123451234516326245372363523632123458913760187501287519875019671647109857108740138475018937460298374610938765410938457109384571039846");
Bignum n2("92759375839475239085472390845783940752398636109570251809571085701287505712857018570198713984570329867103986475103984765109384675109386713984751098570932847510938247510398475130984571093846571394675137846510874510847513049875610384750183274501978365109387460374651873496710394867103984761098347609138746297561762234873519257610");
Bignum n3 = n1*n2;
n3.print();
return 0;
}
as you can see, it's multiply 2 huge integer :) ... (up to 700 digits)
Try this:
//------------DEVELOPED BY:Ighit F4YSAL-------------
#include<iostream>
#include<string>
#include<sstream>
#define BIG 250 //MAX length input
using namespace std;
int main(){
int DUC[BIG][BIG*2+1]={0},n0[BIG],n1[BIG],i,t,h,carry=0,res;
string _n0,_n1;
while(1){
//-----------------------------------get data------------------------------------------
cout<<"n0=";
cin>>_n0;
cout<<"n1=";
cin>>_n1;
//--------------------string to int[]----------------------------------------
for(i=_n0.length()-1,t=0;i>=0,t<=_n0.length()-1;i--,t++){
n0[i]=_n0[t]-'0';
}
i=0;
for(i=_n1.length()-1,t=0;i>=0,t<=_n1.length()-1;i--,t++){
n1[i]=_n1[t]-'0';
}
i=0;t=0;
//--------------------------produce lines of multiplication----------------
for(i=0;i<=_n1.length()-1;i++){
for(t=0;t<=_n0.length()-1;t++){
res=((n1[i]*n0[t])+carry);
carry=(res/10);
DUC[i][t+i]=res%10;
}
DUC[i][t+i]=carry;
carry=0;
}
i=0;t=0;res=0;carry=0;
//-----------------------------add the lines-------------------------------
for(i=0;i<=_n0.length()*2-1;i++){
for(t=0;t<=_n1.length()-1;t++){
DUC[BIG-1][i]+=DUC[t][i];
//cout<<DUC[t][i]<<"-";
}
res=((DUC[BIG-1][i])+carry);
carry=res/10;
DUC[BIG-1][i]=res%10;
//cout<<" ="<<DUC[BIG-1][i]<<endl;
}
i=0;t=0;
//------------------------print the result------------------------------------
cout<<"n1*n0=";
for(i=_n0.length()*2-1;i>=0;i--){
if((DUC[BIG-1][i]==0) and (t==0)){}else{cout<<DUC[BIG-1][i];t++;}
//cout<<DUC[BIG-1][i];
}
//-------------------------clear all-------------------------------------
for(i=0;i<=BIG-1;i++){
for(t=0;t<=BIG*2;t++){
DUC[i][t]=0;
}
n0[i]=0;n1[i]=0;
}
//--------------------------do it again-------------------------------------
cout<<"\n------------------------------------------------\n\n";
}
return 0;
}
This solution is good for very very big numbers but not so effective for factorial calculation of very big numbers. Hope it will help someone.
#include <iostream>
#include <string>
using namespace std;
string addition(string a, string b) {
string ans = "";
int i, j, temp = 0;
i = a.length() - 1;
j = b.length() - 1;
while (i >= 0 || j >= 0) {
if (i >= 0 && a[i])
temp += a[i] - '0';
if (j >= 0 && b[j])
temp += b[j] - '0';
int t = (temp % 10);
char c = t + '0';
ans = ans + c;
temp = temp / 10;
i--;
j--;
}
while (temp > 0) {
int t = (temp % 10);
char c = t + '0';
ans = ans + c;
temp = temp / 10;
}
string fnal = "";
for (int i = ans.length() - 1;i >= 0;i--) {
fnal = fnal + ans[i];
}
return fnal;
}
string multiplication(string a, string b) {
string a1, b1 = "0";
int i, j, temp = 0, zero = 0;
i = a.length() - 1;
int m1, m2;
while (i >= 0) {
a1 = "";
m1 = a[i] - '0';
j = b.length() - 1;
while (j >= 0) {
m2 = b[j] - '0';
temp = temp + m1*m2;
int t = temp % 10;
char c = t + '0';
a1 = a1 + c;
temp = temp / 10;
j--;
}
while (temp > 0) {
int t = (temp % 10);
char c = t + '0';
a1 = a1 + c;
temp = temp / 10;
}
string fnal = "";
// reverse string
for (int i = a1.length() - 1;i >= 0;i--) {
fnal = fnal + a1[i];
}
a1 = fnal;
//add zero
for (int p = 0;p < zero;p++)
a1 = a1 + '0';
b1 = addition(a1, b1);
i--;
zero++;
}
return b1;
}
// upto 50 is ok
int factorial(int n) {
string a = "1";
for (int i = 2;i <= n;i++) {
string b = to_string(i);
a = multiplication(a, b);
}
cout << a << endl;
return a.length();
}
int main() {
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
int n;
cin >> n;
//cout << factorial(n) << endl;
string a, b;
a = "1281264836465376528195645386412541764536452813416724654125432754276451246124362456354236454857858653";
b = "3767523857619651386274519192362375426426534237624548235729562582916259723586347852943763548355248625";
//addition(a, b);
cout << multiplication(a, b);
return 0;
}