编辑代码

class Main {
	public static void main(String[] args) {
        
        String master = "abcaadd";
        String slave = "ad";
        int result = matchStr(master,slave);
        System.out.print("下标为："+result);
        
	}

    public static int matchStr(String master,String slave){
        int masterLen = master.length();
        int slaveLen = slave.length();
        if(masterLen==0||slaveLen==0||masterLen<slaveLen){
            return -1;
        }
        for(int i=0;i<=masterLen-slaveLen;i++){
            int j=0;
            for(;j<slaveLen;j++){
                if(master.charAt(i+j)!=slave.charAt(j)){
                    break;
                }
            }
            if(j==slaveLen){
                return i;
            }
        }
        return -1;
    }

}