Does not display the string, in C

I'm having trouble copying string in C, this does not want to work.

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int count;
    char str1[20] = "Hello World", str2[20];
    for(count = 0; str1[count]!='
#include <stdio.h>
#include <stdlib.h>

int main()
{
    int count;
    char str1[20] = "Hello World", str2[20];
    for(count = 0; str1[count]!='%pre%'; count++)
        str2[count] = str1[count];
    str2[count] = '%pre%';
    printf("%c%", str2[count]);
    system("pause");
    return 0;
}
'; count++)
        str2[count] = str1[count];
    str2[count] = '%pre%';
    printf("%c%", str2[count]);
    system("pause");
    return 0;
}

I have tried with% c, and% s, and with braces in, but nothing appears on the screen,% s appears (null), I know there is the option to use strcpy.