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# how to convert character to integer c++ (urgent )

 P: 11 hiii i am taking input from a file as a character and have to convert it into integer to do some operations eg the character input may be 1 , 0 , 2 etc. and i need to convert them into integers .. i have tried doing unsigned char var_name; int i; i=int( var_name); but it gives wrong output .. probably it is converting the character into ascii.. i cannot understand how to go about it .. please help ... Jun 19 '07 #1
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 Expert Mod 100+ P: 931 hiii i am taking input from a file as a character and have to convert it into integer to do some operations eg the character input may be 1 , 0 , 2 etc. and i need to convert them into integers .. i have tried doing unsigned char var_name; int i; i=int( var_name); but it gives wrong output .. probably it is converting the character into ascii.. i cannot understand how to go about it .. please help ... Use atoi function to convert char to int Cheers! Jun 19 '07 #2

 P: 11 Use atoi function to convert char to int Cheers! hii thankyou!! it works .. by the way .. why cant it convert unsigned char* to const char * ... imean it works when i declare the variable character .. but does not in case i declare the variable unsigned char .. :) Jun 19 '07 #3

 Expert Mod 100+ P: 931 hii thankyou!! it works .. by the way .. why cant it convert unsigned char* to const char * ... imean it works when i declare the variable character .. but does not in case i declare the variable unsigned char .. :) For that try this: unsigned char tmp = 'a'; int num = static_cast(tmp); For the sake of knowledge: The static_cast operator converts expression to the type of type-id based solely on the types present in the expression. No run-time type check is made to ensure the safety of the conversion.( from http://msdn2.microsoft.com/en-us/library/ms861534.aspx) Regards Jun 19 '07 #4

 Expert Mod 5K+ P: 9,197 You don't need atoi. That's a relic C function. You convert a char to an int by assigning the char to the int. Expand|Select|Wrap|Line Numbers char c = 'A'; int x; x = c;    //x contains 65 which is the ASCII value of 'A' c = '2'; x = c;    //x contains 62 which is the ASCII value of '2' x = c - 48;  //x contains 2     A char is just an 8-but integer so you can freely use as an integer. Jun 19 '07 #5

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