C stdlib atof() Function
Example
Read a number from a string:
char str[] = "4.25% above average";
float amount = atof(str);
printf("%f", amount);Definition and Usage
The atof() function reads a representation of a number from a string and
returns its value.
While reading it first skips over any whitespace (spaces, tabs or new lines) and then reads all of the characters until it runs into one which is not part of the number. If the characters it reads do not form a valid number representation then it returns 0.
The atof() function is defined in the <stdlib.h> header file.
Tip: If the number is not at the beginning of the string you can use a pointer to a different position in the string. See More Examples below for an example.
Syntax
atof(const char * str);Parameter Values
| Parameter | Description |
|---|---|
| str | A string containing a representation of a number. |
Technical Details
| Returns: | A double value containing the number represented by
the string. |
|---|
More Examples
Example
Read a number at a specified position in the string:
char str[] = "The results are 4.25% above average";
float amount = atof(&str[16]);
printf("%f", amount);