The C language converts a numeric string to a number corresponding to this string (including positive floating-point numbers, negative floating-point function prototypes: Double my_atof (char *str)

Write a function that converts a numeric string to a number corresponding to the string (including positive floating-point numbers, negative floating-point numbers)

For example: "12.34" returns 12.34

"-123.34" return-123.34

Function prototypes: Doublemy_atof (char *str)

Tips:

You need to judge the minus sign in the function, the decimal point, and whether it is a numeric character. When judging a decimal point, you need to define a counter to calculate the number of numeric characters after the decimal point.

#include <stdio.h> #include <math.h>double my_atof (char *str) {    char *ch = str;    int flag=1;    int point=0;    int count=0;    Double sum = 0;    while (*ch! = ')        } {            if (*ch = = '-')      //Judging minus sign            {                flag =-1;                ch++;            }            if (*ch = = '. ')                  {                point=1;                ch++;            }            if (*ch >= ' 0 ' && *ch <= ' 9 ')            {                sum=sum*10+ (*ch-' 0 ');                ch++;            }            if (point==1)    //encounters a decimal counter plus 1            {                count++;            }        }        Sum=flag*sum*pow (10,-count);    return sum;} int main () {    char *str= "12.83";    Double N;    N=my_atof (str);    printf ("%f\n", n);    return 0;}

The C language converts a numeric string to a number corresponding to this string (including positive floating-point numbers, negative floating-point function prototypes: Double my_atof (char *str)