Using strtol : strtol « stdlib.h « C Tutorial

1. C Tutorial
2. stdlib.h
3. strtol

#include <stdio.h>
#include <stdlib.h>

int main()
{                                 
   const char *string = "-1234567abc"; 
   
   char *remainderPtr; 
   long x;             
   
   x = strtol( string, &remainderPtr, 0 );

   printf( "%s\"%s\"\n%s%ld\n%s\"%s\"\n%s%ld\n",
           "The original string is ", string,
           "The converted value is ", x,
           "The remainder of the original string is ", 
           remainderPtr,
           "The converted value plus 567 is ", x + 567 );

   return 0; 

}

The original string is "-1234567abc"
The converted value is -1234567
The remainder of the original string is "abc"
The converted value plus 567 is -1234000