The way to convert char to int C++.

Question

Have a nice day everyone!

I'm a new learner to C++ and I want to convert char to int C++, but I really don't know what I should do. Can you help me, guys? Please give me some advice. Thanks!

lyytutoria · Accepted Answer

Do you want to convert char to int in C++? Okay, I will help you. Let's follow my suggestions below. In the C++, there are a lot of methods to convert a char type variable into an int, but I find the most effective ways are stringstream, stoi() and typecasting.

1, Stringstream method

A single character represented as a stringstream object can be converted to an integer or any other numeric value. For example: I run following program:

#include 
#include 
#include 
using namespace std;
int main()
{
stringstream str;

str << "8"; int x; str >> x;
cout<<"Converted value of character 8 :"<


Then I receive this output:

Converted value of character 8 :8

2, stoi() method
Below is the program I use stoi() method to convert char to int:

#include 
#include 
using namespace std;
int main() {
char s1[] = "45";
char c = 's';

int x = stoi(s1);
cout << "The value of x : " << x;

int y = (int)(c);
cout << "
The value of y : " << y;

return 0;
}

Output:

The value of x : 45 
The value of y : 115


3, Typecasting method
Assume that there is a character contains a digit, such as 'X,' and I want to convert it to an integer that only has the value X, not the ascii value. If char includes the value '6,' the converted int value should also be 6. Let's look at how I can accomplish this.

#include 
int main()
{
char ch = '6';
// Let's check whether character is digit or not
if (isdigit(ch))
{
// Convert character to integer
int num = ch - '0';
std::cout << num <


The output I get:





54


Let's check whether character contains a digit or not first. If so, subtract the ascii value of the character '0' from it to get the real integer value.
Above are some ways I suggest you. I hope they are useful for you and I have an advice for you. Remember that learning C++ takes a lot of patience, perseverance, and practice. So, let's start from today. Good luck!!!

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