C Language: atoi function
(Convert String to Integer)
In the C Programming Language, the atoi function converts a string to an integer.
The atoi function skips all white-space characters at the beginning of the string, converts the subsequent characters as part of the number, and then stops when it encounters the first character that isn't a number.
Syntax
The syntax for the atoi function in the C Language is:
int atoi(const char *nptr);
Parameters or Arguments
- nptr
- A pointer to a string to convert to an integer.
Returns
The atoi function returns the integer representation of a string. The atoi function skips all white-space characters at the beginning of the string, converts the subsequent characters as part of the number, and then stops when it encounters the first character that isn't a number.
Required Header
In the C Language, the required header for the atoi function is:
#include <stdlib.h>
Applies To
In the C Language, the atoi function can be used in the following versions:
- ANSI/ISO 9899-1990
Similar Functions
Other C functions that are similar to the atoi function:
- atof function <stdlib.h>
- atol function <stdlib.h>
- strtol function <stdlib.h>
- strtoul function <stdlib.h>
See Also
Other C functions that are noteworthy when dealing with the atoi function:
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