import java.util.Scanner;
public class gaohaoA {
    public static void main(String args[]) {
        Scanner reader = new Scanner(System.in);
        double a = 0,b = 0,c = 0;
        System.out.print("输入边a：");
        a = reader.nextDouble();
        System.out.print("输入边b：");
        b = reader.nextDouble();
        System.out.print("输入边c：");
        c = reader.nextDouble();
        if(a + b > c && b + c > a && a + c > b) {
        if(a*a == b*b + c*c || b*b == a*a + c*c || c*c == a*a + b*b) {
            System.out.printf("%-8.3f%-8.3%-8.3f构造是直角三角形",a,b,c);
        }
        else if(a*a < b*b + c*c && b*b < a*a + c*c && c*c < a*a + b*b) {
            System.out.printf("%-8.3f%-8.3%-8.3f构造是锐角三角形",a,b,c);
        }
        else {
            System.out.printf("%-8.3f%-8.3%-8.3f构造是钝角三角形",a,b,c);
        }
    }
    else {
        System.out.printf("%f,%f,%f不构成三角形",a,b,c);
    }

}
}


会出现如下结果：
输入边a：3
输入边b：4
输入边c：5
Exception in thread "main" java.util.IllegalFormatPrecisionException: 3
    at java.util.Formatter$FormatSpecifier.checkText(Formatter.java:2940)
    at java.util.Formatter$FormatSpecifier.<init>(Formatter.java:2647)
    at java.util.Formatter.parse(Formatter.java:2480)
    at java.util.Formatter.format(Formatter.java:2414)
    at (PrintStream.java:920)
    at (PrintStream.java:821)
    at gaohaoA.main(gaohaoA.java:14)

急求~~~谢谢~~~

请问你在写C代码吗？

import java.util.Scanner;
public class gaohaoA {
    public static void main(String args[]) {
        Scanner reader = new Scanner(System.in);
        double a = 0,b = 0,c = 0;
        System.out.print("输入边a：");
        a = reader.nextDouble();
        System.out.print("输入边b：");
        b = reader.nextDouble();
        System.out.print("输入边c：");
        c = reader.nextDouble();
        if(a + b > c && b + c > a && a + c > b) {
        if(a*a == b*b + c*c || b*b == a*a + c*c || c*c == a*a + b*b) {
            System.out.printf("构造是直角三角形",a,b,c);
        }
        else if(a*a < b*b + c*c && b*b < a*a + c*c && c*c < a*a + b*b) {
            System.out.printf("构造是锐角三角形",a,b,c);
        }
        else {
            System.out.printf("构造是钝角三角形",a,b,c);
        }
    }
    else {
        System.out.printf("不构成三角形",a,b,c);
    }

}
}

Java吧~~~~

java里面的输出是 System.out.print("构造是直角三角形"+a+b+c);吧

import java.util.Scanner;
public class gaohaoA {
    public static void main(String args[]) 
    {
        Scanner reader = new Scanner(System.in);
        double a = 0,b = 0,c = 0;
        System.out.print("输入边a：");
        a = reader.nextDouble();
        System.out.print("输入边b：");
        b = reader.nextDouble();
        System.out.print("输入边c：");
        c = reader.nextDouble();
        try{
        if(a + b > c && b + c > a && a + c > b)
        {
            if(a*a == b*b + c*c || b*b == a*a + c*c || c*c == a*a + b*b) 
            {
                System.out.println ("aaa");
                System.out.printf("%f,%f,%f构造是直角三角形",a,b,c);
                }
                else if(a*a < b*b + c*c && b*b < a*a + c*c && c*c < a*a + b*b) 
            {
                System.out.println ("bb");
                System.out.printf("%f,%f,%f构造是锐角三角形",a,b,c);
               }
            else 
               {
                   System.out.println ("cc");
                System.out.printf("%f,%f,%f构造是钝角三角形",a,b,c);
            }
           }
        else 
        {
            System.out.println ("xx");
            System.out.printf("%f,%f,%f不构成三角形",a,b,c);
        }
        }catch(Exception e)
        {
            System.out.println (e.toString());
        }

    }
}

我想是这里出了问题：

("%-8.3f%-8.3%-8.3f构造是直角三角形",a,b,c);

("%-8.3f%-8.3%-8.3f构造是锐角三角形",a,b,c);

("%-8.3f%-8.3%-8.3f构造是钝角三角形",a,b,c);

这个被雷到了～～～～～～好好看语法啊楼主，C和JAVA是像，但不是一样

呵呵，c楼主~~~