CODEWITHSUNDEEP
cfloating-point
user5183731
user5183731

Reputation:

C programming comparing floats

Where is the error in my code, super simple yet the comparisons are not outputting the correct values. This function below is in its own file called: FloatingPointRepresentationsFunctions.c

int FloatCompare(float number1,float number2){
    // Write the function to compare and return the corresponding value
    if(number1 < number2){
        return -1;
    }else if(number2 < number1){
        return 1;
    }else{
        return 0;
    }
}

The functions should return -1 if float 2 is greater then float 1, it should return 1 if float 1 is greater then float 2. It then should return 0 if the float values are equal.

My eclipse console output(mingW):

number1: 12.000000 
number2: 11.000000 
Comp: -1
11.000000 is greater than 12.000000

and here is my main c file:

#include <stdio.h>

int main()
{
    float number1 = 0;
    float number2 = 0;

    int comparison;

    number1=12;
    number2=11;
    printf("number1: %f \nnumber2: %f \n", number1, number2);
    comparison=FloatCompare(number1,number2); // Compare two floating point numbers
    printf("Comp: %d\n", comparison);
    if(comparison==1){
            printf("%f is greater than %f\n",number1,number2);
    }else if(comparison==-1){
                printf("%f is greater than %f\n",number2,number1);
    }else if(comparison==0){
        printf("Number are equal\n");
    }else{
        printf("Error\n");
    }


    return 0;
}

Upvotes: 2

Views: 671

Answers (1)

dbush
dbush

Reputation: 223882

Your main file doesn't have a proper prototype for FloatCompare. This means it assumes the default function definition of int FloatCompare(), which results in the function being called incorrectly and undefined behavior.

You need to add a declaration to your main source file so it knows how to call the function properly.

#include <stdio.h>

int FloatCompare(float number1,float number2);

int main()
{
...
}

Upvotes: 5

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