atoll Function

Converts a string to a long long integer.

Include

<stdlib.h>

Prototype

long long atol(const char *s);

Argument

s

the string to be converted

Return Value

Returns the converted long long integer if successful; otherwise, returns 0.

Remarks

The number may consist of the following:

[whitespace] [sign] digits

Optional whitespace followed by an optional sign, then a sequence of one or more digits. The conversion stops when the first unrecognized character is reached. The conversion is equivalent to (int) strtoll(s, (char **)NULL, 10), except it does no error checking, so errno will not be set.

Example

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

int main(void)
{
  char a[] = " -123456";
  char b[] = "2Number";
  long long x;

  x = atoll(a);
  printf("String = \"%s\"  int = %lld\n", a, x);

  x = atoll(b);
  printf("String = \"%s\"  int = %lld\n", b, x);
}

Example Output

String = " -123456"     int = -123456
String = "2Number"      int = 2