Declaration:
data type name of array[row constant expression][col constant expression];
ex：int a[4][5],score[N][M]
a[i][j]
In the above example, the first index value i specifies a row index, whilst j specifies a column index.
- The C language allows arrays of any type, including arrays of arrays.
- With two-bracket pairs, we obtain a two-dimensional array. This idea can be iterated to obtain arrays of higher dimension.
| Declarations of arrays | Remarks |
| int a[50]; | A one-dimensional array |
| int b[2][3]; | A two-dimensional array |
| int c[2][3][2]; | A three-dimensional array |
ex.
1.Declaration: int a[3][3];
2.logical structure:
3.Assignment：
for(i=0;i<3;i++) or：int a[3][3]={{4,8,11},{5,1,6},{2,9,3}}
for(j=0;j<3;j++)
sacnf(“%d”,&a[i][j]);
storage：
We can think of a[i][j] as the element in the ith row, jth column of the array(counting from 0).
Two Dimensional Array (simple matrix):
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22 | #include<stdio.h>
int main() {
int array[3][3];
int row,column;
// Using nested loop to store values in a 2d array
for(row=0; row<3; row++) {
for(column=0; column<3; column++) {
array[row][column] = row+column;
}
}
// Using nested loop to display vlues of a 2d array
for(row=0; row<3; row++) {
for(column=0; column<3; column++) {
printf("%d\t",array[row][column]);
}
printf("\n");
}
return 0 ;
}
|
Output
The sum of two matrix:
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66 | #include<stdio.h>
int main() {
int i,j,numberOfRows,numberOfCols;
int A[10][10],B[10][10],C[10][10];
printf("Enter number of rows and cols:\n");
scanf("%d %d",&numberOfRows,&numberOfCols);
printf("\nA Matrix:\n");
//input of A matrix from the user
for(i=0; i<numberOfRows; i++) {
for(j=0; j<numberOfCols; j++) {
printf("A[%d][%d]= ",i,j);
scanf("%d",&A[i][j]);
}
printf("\n");
}
printf("\nB Matrix:\n");
//input of B matrix from the user
for(i=0; i<numberOfRows; i++) {
for(j=0; j<numberOfCols; j++) {
printf("B[%d][%d]= ",i,j);
scanf("%d",&B[i][j]);
}
printf("\n");
}
//print A matrix
printf("A = ");
for(i=0; i<numberOfRows; i++) {
printf("\t");
for(j=0; j<numberOfCols; j++) {
printf("%3d ",A[i][j]);
}
printf("\n");
}
//print B matrix
printf("\nB = ");
for(i=0; i<numberOfRows; i++) {
printf("\t");
for(j=0; j<numberOfCols; j++) {
printf("%3d ",B[i][j]);
}
printf("\n");
}
//Adding two matrices A and B and store the sum to the C matrix
for(i=0; i<numberOfRows; i++) {
for(j=0; j<numberOfCols; j++) {
C[i][j] = A[i][j] + B[i][j];
}
}
//print C matrix
printf("\nA + B = ");
for(i=0; i<numberOfRows; i++) {
for(j=0; j<numberOfCols; j++) {
printf("%3d ",C[i][j]);
}
printf("\n");
printf("\t");
}
}
|
Output
Enter number of rows and cols:
3 3
A Matrix:
A[0][0]= 7
A[0][1]= 8
A[0][2]= 2
A[1][0]= 3
A[1][1]= 11
A[1][2]= 9
A[2][0]= 1
A[2][1]= 12
A[2][2]= 4
B Matrix:
B[0][0]= 2
B[0][1]= 7
B[0][2]= 6
B[1][0]= 3
B[1][1]= 7
B[1][2]= 12
B[2][0]= 11
B[2][1]= 5
B[2][2]= 8
A = 7 8 2
3 11 9
1 12 4
B = 2 7 6
3 7 12
11 5 8
A + B = 9 15 8
6 18 21
12 17 12
