Type casting integer to float ?

[RixtronixLAB]

Dear Members,

I want to convert uint32_t to float, the code :

unsigned int dat = 2248;
	float float_val;
	
	

    float_val = (double)(dat);                         
    NRF_LOG_INFO( "float_val = %.3f\n", float_val );  

It's returning nothing, what is missing here ?

Thanks

[Felix Tam]

uint32_t int_value;

float float_val;

float_val = *(float *)&int_value;

or memcpy(&float_val, &int_val, size_of(int_value);

[RixtronixLAB]

then  NRF_LOG_INFO("Float number V2: %.2f",float_val); ?

[RixtronixLAB]

Snipped :

	unsigned int dat = 2248;
	
	

      
    float float_val = *(float *)&dat;	
    
	  NRF_LOG_INFO("Float number: "NRF_LOG_FLOAT_MARKER"\n\r",NRF_LOG_FLOAT(float_val));
	  NRF_LOG_INFO("Float number V2: %.2f",float_val);

I got 0.00 for float_val ??

[RixtronixLAB]

From terminal  :

<info> app: Float number: 0.000
                                               

                               
                                              

nfo> app: Float number V2:
             

Code : 

	uint32_t int_value;
	float float_val;
	
       
    //float_val = *(float *)&int_value;	
    memcpy(&float_val, &int_value, sizeof(int_value));
	  NRF_LOG_INFO("Float number: "NRF_LOG_FLOAT_MARKER"\n\r",NRF_LOG_FLOAT(float_val));
	  NRF_LOG_INFO("Float number V2: %.2f",float_val);

[Felix Tam]

Float in c is IEEE754 format. 1st bit represent sign, the next 8 bits represent expo and the rest 23 bits 

represent fraction. The uint32_t you try is 2248 that the expo is 0. Try this

float x = 1.1;

uint32_t int_value = *(uint32_t *)&x;

//int_value is 1066192077

float y = *(float *) &int_value; 

Or use memcpy, the effect is the same.