From 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 7 Apr 2024 13:41:34 -0500 Subject: new repository --- devdocs/c/string%2Fbyte%2Fatoi.html | 60 +++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 devdocs/c/string%2Fbyte%2Fatoi.html (limited to 'devdocs/c/string%2Fbyte%2Fatoi.html') diff --git a/devdocs/c/string%2Fbyte%2Fatoi.html b/devdocs/c/string%2Fbyte%2Fatoi.html new file mode 100644 index 00000000..b4a114d3 --- /dev/null +++ b/devdocs/c/string%2Fbyte%2Fatoi.html @@ -0,0 +1,60 @@ +

atoi, atol, atoll

Defined in header <stdlib.h> 
int       atoi( const char *str );
+		 
long      atol( const char *str );
+		 
long long atoll( const char *str );
+		 (since C99)

Interprets an integer value in a byte string pointed to by str. The implied radix is always 10.

+

Discards any whitespace characters until the first non-whitespace character is found, then takes as many characters as possible to form a valid integer number representation and converts them to an integer value. The valid integer value consists of the following parts:

+

If the value of the result cannot be represented, i.e. the converted value falls out of range of the corresponding return type, the behavior is undefined.

+

Parameters

+ +
str - pointer to the null-terminated byte string to be interpreted

Return value

Integer value corresponding to the contents of str on success.

+

If no conversion can be performed, ​0​ is returned.

+

Notes

The name stands for "ASCII to integer".

+

Example

#include <stdio.h>
+#include <stdlib.h>
+ 
+int main(void)
+{
+    printf("%i\n", atoi(" -123junk"));
+    printf("%i\n", atoi(" +321dust"));
+    printf("%i\n", atoi("0"));
+    printf("%i\n", atoi("0042")); // treated as a decimal number with leading zeros
+    printf("%i\n", atoi("0x2A")); // only leading zero is converted discarding "x2A"
+    printf("%i\n", atoi("junk")); // no conversion can be performed
+    printf("%i\n", atoi("2147483648")); // UB: out of range of int
+}

Possible output:

+
-123
+321
+0
+42
+0
+0
+-2147483648

References

See also

+ + + + +
+
(C99)
 converts a byte string to an integer value
(function)
+
(C99)
 converts a byte string to an unsigned integer value
(function)
+
(C95)(C99)
 converts a wide string to an integer value
(function)
+
(C95)(C99)
 converts a wide string to an unsigned integer value
(function)
C++ documentation for atoi, atol, atoll
+

+ © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
+ https://en.cppreference.com/w/c/string/byte/atoi +

+
-- cgit v1.2.3