Transpose of a matrix

[Member_14849246]

Supose two matrices are there a[3][3] and b[3][3] we scanned the element in a[][] matrix and b is the transpose of former . NOW when we write a code to assign the values we use for(i=0;i<3;i++) {for(j=0;j<3;j++) b[i][j]=a[j][i]; }//correct but when we do b[j][i]=a[i][j] it gives a wrong result why? since in both the cases all assigning cases are same.

[kalberts]

This should be very easy to trace in a debugger. You don't even tell in which way the result is wrong, and you do not show the declaration to fhe two matrices, so there is really not much information to make a qualified guess.

[CPallini]

Of course the result must be the same. Try

#include using namespace std;

void transp_v1( char tgt[3][3], char src[3][3] );
void transp_v2( char tgt[3][3], char src[3][3] );
void dump( char m[3][3] );

int main()
{
char a[3][3] =
{
{ 'a', 'b', 'c' },
{ 'd', 'e', 'f' },
{ 'g', 'h', 'i' },
};

char b[3][3];
char c[3][3];

transp_v1( b, a);
transp_v2( c, a);

dump(a);
cout << "--------\n";
dump(b);
cout << "--------\n";
dump(c);
cout << "--------\n";
}
void transp_v1( char tgt[3][3], char src[3][3] )
{
for (int i=0; i<3; ++i)
for (int j=0; j<3; ++j)
tgt[i][j] = src[j][i];
}

void transp_v2( char tgt[3][3], char src[3][3] )
{
for (int i=0; i<3; ++i)
for (int j=0; j<3; ++j)
tgt[j][i] = src[i][j];
}

void dump( char m[3][3] )
{
for (int i=0; i<3; ++i)
{
for (int j=0; j<3; ++j)
cout << m[i][j] << " ";
cout << "\n";
}
}

output:

a b c
d e f
g h i

a d g
b e h
c f i

a d g
b e h
c f i

[Member_14849246]

but as per my code its giving wrong result whats wrong with my code i tested many times void main(){ int a[3][3],b[3][3],i,j; for(i=0;i<3;i++) for(j=0;j<3;j++) scanf("%d",&a[i][j]); for(i=0;i<3;i++) {for(j=0;j<3;j++) {printf("%d ",a[i][j]); } printf("\n"); } for(i=0;i<3;i++) {for(j=0;j<3;j++) {b[j][i]=a[i][j]; printf("%d ",b[i][j]); } printf("\n"); } }

[CPallini]

Your code is wrong because you are printing the b matrix while you're updating it (you are printing 'not yet updated' items). Try

#include int main()
{
int a[3][3],b[3][3],i,j;
for(i=0;i<3;i++)
for(j=0;j<3;j++)
scanf("%d",&a[i][j]);

for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
printf("%d ",a[i][j]);
}
printf("\n");
}
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
b[j][i]=a[i][j];
}
printf("\n");
}
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
printf("%d ",b[i][j]);
}
printf("\n");
}
return 0;
}

[jeron1]

b[j][i]=a[i][j];
printf("%d ",b[i][j]);

So you wanted to print the value of b[i][j] after you updated b[j][i]?

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