C删除printf输出

Question

I would like to create a small function, which should show the current status in percentage in the console. The function should only show the current value in the line. So I have to remove the last output. Is that possible? The best case would be some ANSI C stuff, the program should work on linux and windows.

I have found some escape sequences like "\\033[J" , but it dose not work.

Edit

Well I tried it with:

void PrintProcessBar(int i, int n) {
    float ratio = i / (float)n;    
    printf("%.3d\b\b", (int)(ratio * 100));
    fflush(stdout);
}

But it just print lots of zeros... What went wrong? If I use three \\b I get nothing.

Solution

float ratio = (i / (float)n) * 100;
printf("\b\b\b\b");
fflush(stdout);
printf("%.3d%c", (int)ratio, 37);        
fflush(stdout);

i = current position. n = max runs.

I use 4 \\b because, at the first call of the function it will remove 4 spaces.

Greetz.

Answer 1

\\b is the escape sequence for backspace. you can use it with spaces to delete a line.

For example:

printf("98%");
fflush(stdout);
// sleep some time
printf("\b\b\b99%");
fflush(stdout);

This should print 98%, and then replace it with 99%.

Answer 2

What you look for is \\r it is Carriage Return. Makes the carriage go back to the beginning of the line. Do not use \\n as it will go down one line.

Because \\r does not delete text but simply allows you to overwrite, you have to make sure you print enough text (spaces if you need) to clear your line.