remove_multiple_spaces; answer to https://gist.github.com/2227226/

remove_multiple_spaces.c

#include <stdio.h>

int remove_multiple_spaces(char str[]){
    char *result;
    char *cur;
    result = cur = str;
    while (*cur) {
        if (*cur==' ') {
            *result++ = *cur++;
            while (*cur == ' ') {
                cur++;
            }
        }
        else{
            *result++ = *cur++;
        }
    }
    *result = 0;
    return (result - str);
}

int main (int argc, const char * argv[])
{

    char s1[] = "abc    def";
    char s2[] = "  abc    def       ghi";
    char s3[] = " a b   d e ";
    char s4[] = "             ";
    printf("%d,%s\n", remove_multiple_spaces(s1), s1);
    printf("%d,%s\n", remove_multiple_spaces(s2), s2);
    printf("%d,%s\n", remove_multiple_spaces(s3), s3);
    printf("%d,%s\n", remove_multiple_spaces(s4), s4);
    return 0;
}

面试的时候可以写一些unit test