The C language compares the two floating point numbers for the same method, FABS and ABS

I encountered this problem during the interview today, but I was confused at the time. After all, I never used it very much. I remember reading it before and I cannot remember it now! This is a basic C language and is usually used for interviews!

You cannot use = to determine whether the two floating point numbers are equal or not. An error occurs! The two numbers that are clearly equal are not equal!

For two floating point numbers, you can only subtract them and compare them with the preset precision. Remember to take the absolute value!

If (FABS (F1-F2) <pre-specified precision ){...}

Example

# Define Epsilon 0.000001 // If (FABS (Fa-FB) <epsilon) {printf ("fa <FB \ n") According to precision requirements ");}

FABS and ABS Functions

Mathematical function: FABS
Prototype: extern float FABS (float X );

Usage: # include <math. h>

Function: calculates the absolute value of floating point X.

Description: calculation | x |. If X is not negative, X is returned. Otherwise,-X is returned.

Example:

    // fabs.c            #include <syslib.h>      #include <math.h>      main()      {        float x;                clrscr();        // clear screen        textmode(0x00);  // 6 lines per LCD screen                x=-74.12;        printf("|%f|=%f\n",x,fabs(x));        x=0;        printf("|%f|=%f\n",x,fabs(x));        x=74.12;        printf("|%f|=%f\n",x,fabs(x));                getchar();        return 0;      }

The ABS function is for integers.

#include <stdio.h>#include <math.h>int main(){ int x=-10; printf("%d",abs(x));}