You didn't say what compiler you are using. Different compilers have different ways of declaring and printing 64-bit integers. Here is a program that works with gnu c. Let me know if you need one for Borland or Microsoft compilers. I'll tell you what to change.
Code:
/* test long long conversions with gcc
*
* gcc has data type "long long" for 64-bit integers
*
* "%lld" is the conversion specifier for scanf/printf functions
*
*/
#include <stdio.h>
#include <string.h>
long long my_atoll(char *);
int main()
{
char buffer[256];
long long value;
long long value2;
strcpy(buffer, "1234567890123456");
sscanf(buffer, "%lld", &value);
printf("\n\n");
printf(" Value (from sscanf) = %lld\n", value);
value2 = my_atoll(buffer);
printf(" Value (from my_atoll) = %lld\n", value2);
printf("\n\n");
return 0;
}
/*
* ascii-to-longlong conversion
*
* no error checking; assumes decimal digits
*
* efficient conversion:
* start with value = 0
* then, starting at first character, repeat the following
* until the end of the string:
*
* new value = (10 * (old value)) + decimal value of next character
*
*/
long long my_atoll(char *instr)
{
long long retval;
int i;
retval = 0;
for (; *instr; instr++) {
retval = 10*retval + (*instr - '0');
}
return retval;
}
Dave
string to "long long" without using atoll
