public static int rowSum(int[][] d)
{
for (int i = 0; i < d.length; i++)
{
int sum = 0;
for (int j = 0; j < d[i].length; j++)
{
sum = sum + d[i][j];
}
}
return sum;
}
// says cant find symbol "sum"
是的,你试图使用你在一个无效的范围内定义的变量......
public static int rowSum(int[][] d)
{
for (int i = 0; i < d.length; i++)
{
int sum = 0; //definition
for (int j = 0; j < d[i].length; j++)
{
sum = sum + d[i][j];
}
} //scope of sum variable ends here
return sum; //not valid access!!! sum is not defined here.
}
把它放在外面一圈:
public static int rowSum(int[][] d)
{
int sum = 0; //definition
for (int i = 0; i < d.length; i++)
{
for (int j = 0; j < d[i].length; j++)
{
sum = sum + d[i][j];
}
}
return sum; //not valid access!!!
} //scope of sum ends here
但是你还有另外一个问题......你给一个整数添加了两个值......我不确定你是否想要那个,即使你需要得到一个整数,我还要把它们作为双精度加入,并返回一个整数。 ..
public static int rowSum(int[][] d) {
for (int i = 0; i < d.length; i++)
{
int sum = 0;
for (int j = 0; j < d[i].length; j++)
{
sum = sum + d[i][j];
}
}return sum;
}
您在外部for循环块中定义了sun变量,并在该块之外访问它,您应该在循环开始之前初始化它
是的,因为ppeterka66说你必须改变变量的范围。由于块变量对其块可见。所以你需要在main方法中定义sum。
public static int rowSum(int[][] d)
{
int sum = 0;
for ( int i = 0; i < d.length; i++)
{
for (int j = 0; j < d[i].length; j++)
{
sum = sum + d[i][j];
}
}
return sum;
}