Round floating value to .1 (tens place) [duplicate]

Question

Possible Duplicate:
How can I round a float value to 2 post decimal positions?

Lets say I have a double number of 3.46. How do I round it to 3.50? I tried

NSLog(@"res: %.f", round(3.46)); 

but it return 3.

Answer 1

Do some calculations....

float f=3.46;
float num=f+0.05;//3.51
int intNum=num*10;//35
float floatNum=intNum/10.0;//3.5

NSLog(@"res: %.2f", floatNum); //3.50