java开发实战经典（第二版）P157 5-3

5.3   编写程序，统计出字符串“want you to know one thing”中字母n和字母o的出现字数。

package book;

public class JiOu {
	public static void main(String[] args) {
		String str = "want you to know one thing";
		char a[] = str.toCharArray();
		int num1 = 0;
		int num2 = 0;
		for (int i = 0; i < a.length; i++) {
			if (a[i] == 'n') {
				num1++;
			}
			if (a[i] == 'o') {
				num2++;
			}
		}
		System.out.println("n的个数:" + num1);
		System.out.println("n的个数:" + num2);
	}

}

运行结果为:

n的个数:4
n的个数:4