conversion from int to char

[gurupot]

Hi,

I am trying to write to a binary file and while I am setting the values I have to convert an int to a char using
rec.cStopReason = (char) m_nStopCode; where the defnitions are as follows.
char cStopReason; //25
int m_nStopCode;

For all the values in m_nstopcode it works fine but when I have the value as 128 in m_nstopcode I get cStopReason as -128.

Can anyone help me understand why it is doing that.

Thanks,
Pushpa.

[laitinen]

its because you are using a signed char. If you will not have negative values, unsigned char is better and have twice the positive range of a signed char.

[Zaccheus]

On most computers, a char can only range from -128 to 127.

[Skizmo]

rec.cStopReason = (unsigned char) m_nStopCode;

[laitinen]

rec.cStopReason = (unsigned char) m_nStopCode;

You think this will work?:

char cStopReason;
int m_nStopCode = 128;

cStopReason = (unsigned char) m_nStopCode;

cStopReason is still a signed char, hence it cannot handle the value of 128 and will wrap over to -128!

To make this work you'll need to declare cStopReason as unsigned char;

unsigned char cStopReason; //25
int m_nStopCode = 128;

cStopReason = (unsigned char) m_nStopCode;

Best regards,

Laitinen