How to do this.

[time to c]

How to convert char to int
Like I want to convert char x[]='1' into int y=1.

[Zhuge]

Because of how ASCII values work, you can take '1' - '0' == 1, if that's what you are asking.

[time to c]

may be i should ask my question with details so here it is......

#include<iostream>

using namespace std;

int main()
{
           char x[]="29";
           int num;

           // and here should be the piece of code which will convert char data into int
          ?????????????????????????;
          ?????????????????????????;

          //and the value of "char x" should be passed to "int num" without changing it

          cout<<"the value of num is  = "<<num;
          return 0;
}

so the output should look like this.

the value of num is = 29

and also i would like to know how to do vice versa

[zb0S216C]

I think you want std::atoi( )^[1].

References:
^[1]http://www.cplusplus.com/reference/clibrary/cstdlib/atoi/

_Wazzak

[z05DSL3A]

http://www.cplusplus.com/reference/clibrary/cstdlib/atoi/

[time to c]

thanks that worked but i still have one question (i am a noob)

#include<iostream>

using namespace std;

int main()
{
      char x[256];
      int num=923;
            
       //piece of code
       ??????????;
       //finish

        cout<<"the value of x is = "<<x;
        return 0;
} 

output

the value of x is = 923

i just want to convert a numerical char to int data.

i hope i am not missing something about atoi()

[Zhuge]

You can use a stringstream for something like that, I think.

stringstream ss;
ss<<num;
cout<<ss.str();

[smileff]

To convert chars to int, your use sprintf

char x[256];
int num = 923;
sprintf(x, "%d", num);

[sohguanh]

Long long time ago I do some testing on some data volume and somewhow C++ stringstream class is very slow in comparison to say sprintf. The effect is only noticeable if say you want to do such conversion a million times perhaps ?

[time to c]

Thank you everyone for help.