无符号字符范围是 0 到 255

Question

#include <iostream> 
using namespace std; 
int main() 
{ 
    unsigned char counter = 0; 
    for (counter = 0; counter <= 255; counter++) { 
        printf("%d ", counter); 
    } 
    return 0; 
} 

Correct Output is Infinite loop But I thought output is 0,1,...255 because unsigned char ranges from 0 to 255.when the counter becomes 256 then only it exceeds the range. but here our condition is counter <=255 Please clear my doubt

Answer 1

Think about unsigned char as a Byte: 0 -> 0b00000000 1 -> 0b00000001... 255 -> 0b11111111

Then the next number is 0 because you can't have a 9th bit. So after 0b11111111 it's 0b00000000.

That's why it is an infinite loop, it will never reach 256 and will always stay between 0 and 255.

Answer 2

This will result in infinite loop because condition (counter <= 255) in if loop is always true .

There is no way for this condition to be false : variable counter can not contain values higher than 255.