C library function - atof()

Description

The C library function double atof(const char *str) converts the string argument str to a floating-point number (type double).

Declaration

Following is the declaration for atof() function.

double atof(const char *str)

Parameters

• str − This is the string having the representation of a floating-point number.

Return Value

This function returns the converted floating point number as a double value. If no valid conversion could be performed, it returns zero (0.0).

Example

The following example shows the usage of atof() function.

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

int main () {
   float val;
   char str[20];
   
   strcpy(str, "98993489");
   val = atof(str);
   printf("String value = %s, Float value = %f\n", str, val);

   strcpy(str, "tutorialspoint.com");
   val = atof(str);
   printf("String value = %s, Float value = %f\n", str, val);

   return(0);
}

Let us compile and run the above program that will produce the following result −

String value = 98993489, Float value = 98993488.000000
String value = tutorialspoint.com, Float value = 0.000000