Convert char to int in C and C++?

Question

How do I convert a `char` to an `int` in C and C++?

Answer 1

My quick answer is to tell you to cast one to the other:

char ch = 'a';

int x = (int)ch;

int y = int(ch);

But I have to wonder if what you're looking for is something more along the line of taking '7' which is the ASCII character seven and you want to convert it to the integer value of 7. If that is the case, then you need to know that the each character digit has an ASCII code value and that they are sequential from 0 to 9. This permits you to do the following:

int val = int( ch - '0');

#include <iostream>

using namespace std;

int main()

{

for( char ch = '0'; ch <= '9'; ++ch )

{

int val = int( ch - '0');

cout << "ch=" << ch << "\tval=" << val << endl;

}

return 0;

}

Answer 2

Guessing you mean a character number, like '9' or '7' and you want to convert it to it's numeric value. The char variable is holding the ASCII value of '9' or '7' in them (if you look it up, 9 is 0x39 hex and 7 is 0x37 hex). The ASCII table shows the value of '0' to '9' are sequential, so to convert them you can subtract the ASCII value of '0':

char chr = '7';

int num = chr - '0';

cout << "chr=" << chr << endl;

cout << "num=" << num << endl;