converting string to double in c -

i having problem converting string double. please me out.

here's code:

char price[100]; double newprice; printf("\nplease enter price:"); fgets(price,100,stdin); newprice = atof  (price); printf("\nprice of item %f",newprice); 

it gives diff output while running diff files.

file1 (method 1):

char   price[100]; double newprice;  int main() {     myval();     return 0; }  myval() {     printf("\nplease enter price:");     fgets(price, 100, stdin);      newprice = atof(price);     printf("\nprice of item %f", newprice);   } 

file2 (method 2)

#define max 50  char    oldprice[max]; double  newprice;  int main() {     userinput();  }  int userinput() {     printf("\nplease enter price:");     fgets(oldprice, max, stdin);      newprice = atof(oldprice);     printf("\nprice of item %f", newprice);        return 0; } 

the above 2 methods compiled using tcc(tiny compiler). both methods same , diff output these 2. output 1:

d:\>new.exe  please enter price:12.3  price of item 12.300000 

output 2:

d:\>t.exe  please enter price:12.3  price of item 7735248.000000 

you must include <stdlib.h> right prototype atof:

double atof(const char *); 

with that, behaviour expected. (i reckon included first snippet, not second.)

the compiler should warn using function without prototype. using function without prototype legal in c89, compiler assume return value int. , printig value type-unaware printf seems lead strange output.

in c99 , newer standards, illegal use function without prototype. recommend use @ least c99 if compiler supports it. minimum, turn on compiler warnings.