CODEWITHSUNDEEP
c++loops
Ali Zahr
Ali Zahr

Reputation: 64

C++ Terminate loop using a char input to int

I'm trying to input values into an array of size 10, but the problem here is that I want if the users wants to enter 4x4 matrix, he doesn't need to complete till the 10th element in the array, he can simply press 'f' or any character, I tried to make if(input == 'f') but it loops till the end of the array. How can this be solved?

int main() {
int input,flag=0, size=0;
int matrix[10][10] = {0};

for(int i=0; i<10; i++) {
    for(int j=0; j<10;j++) {
        cout << "Please enter data for Row " << i << " Column " <<j << " (-200 to terminate): \n";
        cin >> input;

        if(input == -200) {
            flag = 1;
            break;
        }
        else
            matrix[i][j] = input;
    }
    if(flag == 1)
        break;
    size++;
}

cout << "The determinant of the matrix is: " << determinant(matrix,size) << "\n";
return 0; }

Upvotes: 1

Views: 1590

Answers (3)

rajenpandit
rajenpandit

Reputation: 1361

As R Sahu told that You have to change your strategy of reading the input. So you can also use stringstream to get the solution 

#include <iostream>
#include <sstream>
using namespace std;
int main() {
int input,flag=0, size=0;
int matrix[10][10] = {0};
string s;

for(int i=0; i<10; i++) {
        for(int j=0; j<10;j++) {
                cout << "Please enter data for Row " << i << " Column " <<j << " (-200 to terminate): \n";
                cin >> s;
                stringstream ss(s);
                ss>>input;
                if(ss==0)
                {
                        if(s == "f") {//user don't want to enter further input
                                flag = 1;
                                break;
                        }
                        else
                        {
                                //invalid data so you need to reset the value of i and j;
                        }
                }
                else
                {
                        cout<<"Input:"<<input<<endl;
                        matrix[i][j] = input;
                }
        }
    if(flag == 1)
        break;
    size++;
}

Upvotes: 0

Ruslan Gerasimov
Ruslan Gerasimov

Reputation: 1782

This happens because the exit criteria is the value -200, when you input -200 then all cylces stop working, finish.

Upvotes: 0

R Sahu
R Sahu

Reputation: 206717

You have to change your strategy of reading the input. Read the token as a string. If the first character of the string is 'f', the break out of the loop. Otherwise, extract the number from the string.

int main()
{
   std::string input;
   int flag=0;
   int size=0;
   int matrix[10][10] = {0};

   for(int i=0; i<10; i++) {
       for(int j=0; j<10;j++) {
           std::cout << "Please enter data for Row " << i << " Column " <<j << " (f to terminate): \n";
           std::cin >> input;

           if ( input[0] == 'f' ){
               flag = 1;
               break;
           }
           else
              matrix[i][j] = atoi(input.c_str());
       }
       if(flag == 1)
          break;
       size++;
   }
}

Upvotes: 1

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