求助，实在写不出来，各位大佬可以帮帮忙吗

#include <stdio.h>
#include <stdbool.h>

bool insert( int buf[], size_t capacity, size_t* size, int value )
{
    if( capacity <= *size )
        return false;

    // 使用“二分法”找到第一个“大于value”的值的位置
    size_t index = 0;
    if( buf[0] > value )
        index = 0;
    else if( buf[*size-1] <= value )
        index = *size;
    else
        for( size_t a=0,b=*size; a+1!=b; )
        {
            index = a + (b-a)/2;
            if( buf[index] <= value )
                a = index;
            else
                b = index;
        }


    // 往后挪一位，用 memmove 当然更好
    ++*size;
    for( ; index!=*size; ++index )
    {
        int tmp = buf[index];
        buf[index] = value;
        value = tmp;
    }
    return true;
}

void test( int buf[], size_t capacity, size_t* size, int value )
{
    bool b = insert( buf, capacity, size, value );
    printf( "%s:", b?"插入成功":"容器已满" );
    for( size_t i=0; i!=*size; ++i )
        printf( " %d%c", buf[i], ",\n"[i+1==*size] );
}

int main( void )
{
    int buf[5];
    size_t size = 0;

    test( buf, sizeof(buf)/sizeof(*buf), &size, 2 );
    test( buf, sizeof(buf)/sizeof(*buf), &size, 0 );
    test( buf, sizeof(buf)/sizeof(*buf), &size, 4 );
    test( buf, sizeof(buf)/sizeof(*buf), &size, 1 );
    test( buf, sizeof(buf)/sizeof(*buf), &size, 3 );
    test( buf, sizeof(buf)/sizeof(*buf), &size, 5 );
}