C语言 如何在 c 中创建一个二维数组并使用指针和函数显示它？
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How do i create a 2D array in c and display it using pointer and function?
提问by PhoonOne
I am trying to write 2 functions, one to read the matrix (2D array) and other one to print it out. So far I have:
我正在尝试编写 2 个函数，一个用于读取矩阵（二维数组），另一个用于打印出来。到目前为止，我有：
/* Read a matrix: allocate space, read elements, return pointer. The
number of rows and columns are given by the two arguments. */
double **read_matrix(int rows, int cols){
double **mat = (double **) malloc(sizeof(double *)*rows);
int i=0;
for(i=0; i<rows; i++){
/* Allocate array, store pointer */
mat[i] = (double *) malloc(sizeof(double)*cols);
//what to do after??
return mat;
}
then the print matrix function, not sure if it is correct
然后是打印矩阵功能，不确定是否正确
void print_matrix(int rows, int cols, double **mat){
for(i=0; i<rows; i++){ /* Iterate of each row */
for(j=0; j<cols; j++){ /* In each row, go over each col element */
printf("%f ",mat[i][j]); /* Print each row element */
}
}
}
and here is the main function I am using to run:
这是我用来运行的主要功能：
#include <stdlib.h>
double **read_matrix(int rows, int cols);
void print_matrix(int rows, int cols, double **mat);
void free_matrix(int rows, double **mat);
int main(){
double **matrix;
int rows, cols;
/* First matrix */
printf("Matrix 1\n");
printf("Enter # of rows and cols: ");
scanf("%d %d",&rows,&cols);
printf("Matrix, enter %d reals: ",rows*cols);
matrix = read_matrix(rows,cols);
printf("Your Matrix\n"); /* Print the entered data */
print_matrix(rows,cols,matrix);
free_matrix(rows, matrix); /* Free the matrix */
return 0;
}
回答by Grijesh Chauhan
Try this one. may be helpful to you.
试试这个。可能对你有帮助。
#include <stdio.h>
#include <stdlib.h>
double **read_matrix(int rows, int cols);
void print_matrix(int rows, int cols, double **mat);
void free_matrix(int rows, double **mat);
double **read_matrix(int rows, int cols){
double **mat = (double **) malloc(sizeof(double *)*rows);
int i=0,j=0;
for(i=0; i<rows; i++)
/* Allocate array, store pointer */
mat[i] = (double *) malloc(sizeof(double)*cols);
for(i=0; i<rows; i++){
for(j=0; j<cols; j++){
scanf("%lf",&mat[i][j]);
}
}
return mat;
}
void print_matrix(int rows, int cols, double **mat){
int i=0,j=0;
for(i=0; i<rows; i++){ /* Iterate of each row */
for(j=0; j<cols; j++){ /* In each row, go over each col element */
printf("%lf ",mat[i][j]); /* Print each row element */
}
printf("\n");
}
}
void free_matrix(int rows, double **mat){
int i=0;
for(i=0;i<rows;i++)
free(mat[i]);
free(mat);
}
int main(){
double **matrix;
int rows, cols;
/* First matrix */
printf("Matrix 1\n");
printf("Enter # of rows and cols: ");
scanf("%d%d",&rows,&cols);
printf("Matrix, enter %d reals: \n",rows*cols);
matrix = read_matrix(rows,cols);
printf("Your Matrix\n"); /* Print the entered data */
print_matrix(rows,cols,matrix);
free_matrix(rows, matrix); /* Free the matrix */
return 0;
}
Execution:
执行：
:~$ gcc exam.c
:~$ ./a.out
Matrix 1
Enter # of rows and cols: 3
4
Matrix, enter 12 reals:
1
2
3
4
5
6
7
8
9
9
0
1
Your Matrix
1.000000 2.000000 3.000000 4.000000
5.000000 6.000000 7.000000 8.000000
9.000000 9.000000 0.000000 1.000000
