Wait for milliseconds in C++

#include<iostream>
#include<time.h>
using namespace std;
void delay(clock_t a)
{
    clock_t start;
    start  = clock();
    while(clock()-start<a)
    {

    }
}
int main()
{
    delay(100);
    cout << "A";
    delay(100);
    cout << "h";
    delay(100);
    cout << "m";
    delay(100);
    cout << "e";
    delay(100);
    cout << "d";
    delay(100);
}