double sum = ;
for(int I = ;我& ltm .长度;i++){
for(int j = ;j & ltm[i]。长度;j++){
sum+= m[I][j];返回总和;}
就这样就行了 测试方法如下:
public static void main(String[]args){
int[][]m = { { 1,2},{3,4,5},{6,7},{8,9,1 } };
double sum = sum matrix(m);
system . out . println(sum);
}