My code

=======

#include<iostream.h>

void identity(int a[4][4], int m){

int i=m, j=m;

for(i=0;i<4;i++){

for(j=0;j<4;j++){

if(i==j)

a[i][j]=1;

else

a[i][j]=0;

return a[i][j];

}

}

}

void main(){

int a[4][4];

int m=4;

identity(a[4][4], m);

cout<a[i][j]

}

cout<<'\n';

}

My problem

==========

Write a function 'identity' which returns a 1 if the array argument passed to it represents an identity matrix, and returns 0 otherwise. An identity matrix is an m by m array of integers, where the values of the elements on the principle diagonal (row subscript == col subscript)equal 1, and all other elements are 0. for

example:

1 0 0 0

0 1 0 0

0 0 1 0

0 0 0 1

is an identity matrix of order 4 by 4,

1 0 0

0 1 0

0 0 1

is an identity matrix of order 3 by 3,and

1 1 5

0 1 0

0 0 1

is NOT an identity matrix. The function identity is passed two arguments: the array, and the order of the matrix ( i e the size of the two dimensions). Thus the prototype of the function would be written as :int identity (int a[][], int m);where a is the array and m represents the number of rows and columns. You may assume that the number of rows always equals the number of columns for the array.

=======

#include<iostream.h>

void identity(int a[4][4], int m){

int i=m, j=m;

for(i=0;i<4;i++){

for(j=0;j<4;j++){

if(i==j)

a[i][j]=1;

else

a[i][j]=0;

return a[i][j];

}

}

}

void main(){

int a[4][4];

int m=4;

identity(a[4][4], m);

cout<a[i][j]

}

cout<<'\n';

}

My problem

==========

Write a function 'identity' which returns a 1 if the array argument passed to it represents an identity matrix, and returns 0 otherwise. An identity matrix is an m by m array of integers, where the values of the elements on the principle diagonal (row subscript == col subscript)equal 1, and all other elements are 0. for

example:

1 0 0 0

0 1 0 0

0 0 1 0

0 0 0 1

is an identity matrix of order 4 by 4,

1 0 0

0 1 0

0 0 1

is an identity matrix of order 3 by 3,and

1 1 5

0 1 0

0 0 1

is NOT an identity matrix. The function identity is passed two arguments: the array, and the order of the matrix ( i e the size of the two dimensions). Thus the prototype of the function would be written as :int identity (int a[][], int m);where a is the array and m represents the number of rows and columns. You may assume that the number of rows always equals the number of columns for the array.

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Start your 7-day free trialAnyway, as posed in the question, one cannot write such as function (it ain't valid C or C++). If a was a flat array of m*m elements then that could be easily done.

C++

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/* no point in passing int m=4 if a[4][4] is hard coded */

/* the question you were given is not possible to answer */

/* exactly as specified. but we cannot do much */

/* about that now... */

/* also the function should return an int not a void */

/* void identity(int a[4][4], int m) { */

int identity(int a[4][4], int m) {

/* no point initializing i and j as they are */

/* set in the loop */

/* int i=m; */

/* int j=m; */

int i;

/* you have hard-coded 4 in the for loops */

/* for(i=0;i<4;i++){ */

/* for(j=0;j<4;j++){ */

/* we should use 'm' instead */

for(i=0;i<m;i++){

/* declare j here where it is used */

/* this is nicer code */

int j;

for(j=0;j<m;j++){

/* this is CREATING an identity matrix */

/* NOT testing for one as was asked */

if(i==j)

a[i][j]=1;

else

a[i][j]=0;

/* this is not what should be returned */

return a[i][j];

}

}

/* no return value from here at all */

/* a good compiler will detect this error */

}

int main(int argc, char* argv[]) {

/* you haven't put any data into a[][] yet */

int a[4][4];

int m=4;

/* you haven't done anything with the */

/* return value from identity */

/* also the call is wrong .. you are passing */

/* the value of the [4][4] item of the array */

/* (which is outside it anyway) instead of the */

/* whole array */

/* identity(a[4][4], m); */

int result = identity(a, m);

/* i and j aren't defined */

/* and you should be printing the result of */

/* the call to identity(...); */

/* BTW: if this is supposed to be 'C' code */

/* then you cannot use 'cout<<' etc */

/* cout<<a[i][j]; */

cout << result;

cout<<'\n';

return 0;

}

/* I suggest you think about the question */

/* a bit more and come back to me */