CODEWITHSUNDEEP
ctype-conversion
Vicky
Vicky

Reputation: 37

Type Casting from char * to int

How can I store the value pointed by the char pointer into an integer variable? I have the following code:

main ()
{
  int i;
  char *tmp = "10";
  i = (int)tmp;
  printf("value of i is %d",i);
}

Is my code most efficient for the given task? I am using Visual Studio 2008.

Upvotes: 1

Views: 281

Answers (2)

Emil Vikström
Emil Vikström

Reputation: 91983

A string in C is just an array of characters, and tmp points to the first character in the string. Your code converts this pointer value (a memory address) to an integer and stores it in i.

What you really want to do is use strtol in stdlib:

#include <stdlib.h>
main ()
{
  int i;
  char *tmp = "10";
  i = (int) strtol(tmp, 0, 10);
  printf("value of i is %d",i);
}

Upvotes: 3

Oren
Oren

Reputation: 4252

You should probably look into atoi for string to int conversions.

Note that atoi does no error checking so only use it if you know exactly what your input is (like the constant string you have in your example). Otherwise use Emil Vikström's answer.

Upvotes: 1

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