how to split a string for equation

by

To extract characters from a string and to store them into a Character Array

Simple Method (Using string indexing):

#include<iostream>

using namespace std;
// Using the namespace std to use string.

int main(int argc, char** argv) {
    string input;
    cout << "Enter a string: ";
    cin>>input;     // To read the input from the user.
    
    int strLength = input.length(); // To compute the length of the string.
    char * charArray = new char[strLength]; //Dynamic memory allocation

    /**
     * The following for loop converts the string into an array.
    */
    for (int i=0; i<strLength; i++) {
        charArray[i] = input[i];
    }

    cout << endl << "The elements of the character array are as follows: {";
    for (int i = 0; i < strLength; i++) {
        if (i != strLength - 1) {
            cout << "\'" << charArray[i] << "\', ";
        } else {
            cout << "\'" << charArray[i] << "\'}";
        }   
    }

    delete [] charArray;
    return 0;
}

Sample Output:

Enter a string: Hello

The elements of the character array are as follows: {'H', 'e', 'l', 'l', 'o'}
RUN SUCCESSFUL (total time: 3s)

To handle more complex inputs or if you are interested in a more complex structure, the following program should help you:

#include<iostream>

using namespace std;
// Using the namespace std to use string.

int main(int argc, char** argv) {
    string input;
    cout << "Enter a string: ";
    cin>>input;     // To read the input from the user.
    
    int strLength = input.length(); // To compute the length of the string.
    char * charArray = new char[strLength]; //Dynamic memory allocation
    int loopVar = 0;

    /**
     * The following for loop converts the string into an array.
    */
    for (const char* iterativeVar = input.c_str(); *iterativeVar; iterativeVar++) {
        charArray[loopVar] = *iterativeVar;
        ++loopVar;
    }

    cout << endl << "The elements of the character array are as follows: {";
    for (int i = 0; i < strLength; i++) {
        if (i != strLength - 1) {
            cout << "\'" << charArray[i] << "\', ";
        } else {
            cout << "\'" << charArray[i] << "\'}";
        }   
    }

    delete [] charArray;
    return 0;
}

Sample Output:

Enter a string: Hello

The elements of the character array are as follows: {'H', 'e', 'l', 'l', 'o'}
RUN SUCCESSFUL (total time: 2s)

Remember to use const char * in the for loop. Otherwise you will get an error as follows:

newmain.cpp: In function 'int main(int, char**)':
newmain.cpp:23:42: error: invalid conversion from 'const char*' to 'char*' [-fpermissive]
     for (char* iterativeVar = input.c_str(); *iterativeVar; iterativeVar++) {

Do not forget to deallocate the memory using delete which was allotted to the character array using new operator as shown below:

delete [] charArray;

Otherwise, you may encounter memory leaks in your program.

To extract characters which are integers from a string and to store them into an Integer Array:

The following program should help you:

#include<iostream>

using namespace std;
// Using the namespace std to use string.

int main(int argc, char** argv) {
    string input;
    cout << "Enter a number: ";
    cin>>input;     // To read the input from the user.
    
    int strLength = input.length(); // To compute the length of the string.
    int * intArray = new int[strLength]; //Dynamic memory allocation
    int loopVar = 0;

    /**
     * The following for loop converts the string into an array.
    */
    for (const char* iterativeVar = input.c_str(); *iterativeVar; iterativeVar++) {
        intArray[loopVar] = (*iterativeVar-'0');
        ++loopVar;
    }

    cout << endl << "The elements of the integer array are as follows: {";
    for (int i = 0; i < strLength; i++) {
        if (i != strLength - 1) {
            cout << intArray[i] << ", ";
        } else {
            cout <<intArray[i]<<"}";
        }   
    }

    delete [] intArray;
    return 0;
}

Sample Output:

Enter a number: 123456789

The elements of the integer array are as follows: {1, 2, 3, 4, 5, 6, 7, 8, 9}
RUN SUCCESSFUL (total time: 4s)

More Related Contents:

  1. What is the most efficient C++ method to split a string based on a particular delimiter similar to split method in python? [closed]
  2. How do I iterate over the words of a string?
  3. How do I tokenize a string in C++?
  4. Split a string using C++11
  5. How to make my split work only on one real line and be capable to skip quoted parts of string?
  6. C++ – repeatedly using istringstream
  7. cannot convert ‘std::string’ to ‘char**’ for argument ‘1’ to ‘__ssize_t getline(char**, size_t*, FILE*)’
  8. Why the switch statement cannot be applied on strings?
  9. Converting a hex string to a byte array
  10. How does strtok() split the string into tokens in C?
  11. Static constant string (class member)
  12. Split a string with delimiters but keep the delimiters in the result in C#
  13. “\n” or ‘\n’ or std::endl to std::cout? [duplicate]
  14. Using getline() in C++
  15. How to reverse an std::string? [duplicate]
  16. Are there any better methods to do permutation of string?
  17. Difference between and ?
  18. Deprecated conversion from string literal to ‘char*’
  19. How to convert UTF-8 std::string to UTF-16 std::wstring?
  20. How do I replace all instances of a string with another string?
  21. C++ Remove punctuation from String
  22. sizeof in c++ showing string size one less
  23. Why does calling std::string.c_str() on a function that returns a string not work?
  24. C++ function to count all the words in a string
  25. Why doesn’t std::string provide implicit conversion to char*?
  26. variable or field declared void
  27. How can I make the map::find operation case insensitive?
  28. string::size_type instead of int
  29. How to convert a string of hex values to a string?
  30. Where are string literals stored, and can I modify them?

Leave a Comment