"Turbo C 编译器问题，sqrt() 函数不适用于可变参数"

Question

I searched the question similar to my problem Similar problem<\/a> . But my problem is when using Turbo C compiler v3.0. Should I have to do some additional work for math.h file? please help.

int main (void){
    double result, a;
    clrscr();
    printf("Enter a # for square root.\n");
    scanf("%f",&a);
    printf("a = %f\n",a);
    result = sqrt(a);
    printf("a = %f  and square root is %f\n",a, result);
    getch();
    return 0;
    }

Answer 1

For scanf() , %f is for float . You need to use %lf for double :

printf("Enter a # for square root.\n");
scanf("%lf",&a);

This is in contrast to printf() where type-promotion allows %f to be used for both float and double .

Answer 2

Try this :

   scanf("%lf",&a);

or change the variable a to float:

 float a;

Answer 3

In addition to using "%lf" as the scanf format, you need to have

#include <stdio.h>
#include <math.h>
#include <conio.h> /* I think */

The last one is for the clrscr() and getch() calls; they're non-standard, but I think they're declared in <conio.h> .

Without the #include <math.h> , the compiler is going to assume that sqrt() returns an int result rather than double .

(An aside: Why do you call clrscr() ? What is the benefit of clearing the screen before doing anything else? The getch() call isn't strictly necessary either, but on some systems the default method of running a program results in the window being closed as soon as it terminates.)

Answer 4

Declare variable a in float and variable result in double, and use math.h header file
And use to take input ("%f", &a); for taking input
And then result = sqrt(a);
and print result in "%lf" format
it works perfectly in turbo c

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