4-3

#include<stdio.h>
int main(void)
{
    int count,number;
    count=0;
    printf("Enter a number:");
    scanf("%d",&number);
    if(number<0)number=-number;
    do{
        number=number/10;
        count++;
    }while(number!=0);
    printf("It contains %d digits.
",count);
    return 0;
}