Question

What is the difference between float and double in C

Answer 1

// double has 2x the precision than float

#include <stdio.h> 
#include <math.h> 

void float_calc(float a) { 
    float n = a / 98;
    float sum = 0;

    for (int i = 0; i < 817; i++)
            sum += n;

    printf("%.7g\n", sum);   

} 
  
void double_calc(double a) { 
    double n = a / 98;
    double sum = 0;

    for (int i = 0; i < 817; i++)
            sum += n;

    printf("%.7g\n", sum);  
} 
  
int main(int argc, char **argv)
{ 
    float fa = 1.0f; 
    double da = 1.0; 
  
	printf("float\n");
    float_calc(fa); 
	
	printf("\ndouble\n");
    double_calc(da); 
    
    return 0; 
}   


/*
run:

float
8.336832

double
8.336735

*/

 

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