I m trying to build a 2*2 array but my program asks for 5 inputs. Why?
0
I couldn't zero down where i have missed in the input statement. I have build it to acquire four values as input but it goes one more.
manipulating the array entries to check if the fifth value is stored. Basic things
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=1;i<=2;i++)
{
for(j=1;j<=2;j++)
scanf("%dt",&a[i][j]);
}
printf("n%dt%dn%dt%d", a[1][1],a[1][2],a[2][1],a[2][2]);
}
c for-loop
edited Jan 2 at 9:24
Mat
166k29316347
asked Jan 2 at 9:21
F.FredF.Fred
62
add a comment |
0
I couldn't zero down where i have missed in the input statement. I have build it to acquire four values as input but it goes one more.
manipulating the array entries to check if the fifth value is stored. Basic things
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=1;i<=2;i++)
{
for(j=1;j<=2;j++)
scanf("%dt",&a[i][j]);
}
printf("n%dt%dn%dt%d", a[1][1],a[1][2],a[2][1],a[2][2]);
}
c for-loop
edited Jan 2 at 9:24
Mat
166k29316347
asked Jan 2 at 9:21
F.FredF.Fred
62
When you declare an array with two entries, likea[2], the only valid indexes are 0 and 1. But the loops and the printf are using indexes 1 and 2. One solution is to make the array biggerint a[3][3].
– user3386109
Jan 2 at 9:26
1
In C the array starts at 0 not 1, so the declared arraya[2][2]containsa[0][0]uptoa[1][1].
– Tom Kuschel
Jan 2 at 9:28
a[1][2]anda[2][1]anda[2][2]do not exist. Your array has 4 elements:a[0][0],a[0][1],a[1][0], anda[1][1].
– pmg
Jan 2 at 9:28
thanks for the advice... but It doesn't seem to work that way.. it is what we define in the for loop as i am able to get the results as expected. When i printed, a[0][0]..a[1][1], all values except a[1][1] had zeroes..
– F.Fred
Jan 2 at 10:03
Read How to debug small programs.
– Basile Starynkevitch
Jan 2 at 10:12
add a comment |
0
0
0
I couldn't zero down where i have missed in the input statement. I have build it to acquire four values as input but it goes one more.
manipulating the array entries to check if the fifth value is stored. Basic things
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=1;i<=2;i++)
{
for(j=1;j<=2;j++)
scanf("%dt",&a[i][j]);
}
printf("n%dt%dn%dt%d", a[1][1],a[1][2],a[2][1],a[2][2]);
}
c for-loop
edited Jan 2 at 9:24
Mat
166k29316347
asked Jan 2 at 9:21
F.FredF.Fred
62
I couldn't zero down where i have missed in the input statement. I have build it to acquire four values as input but it goes one more.
manipulating the array entries to check if the fifth value is stored. Basic things
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=1;i<=2;i++)
{
for(j=1;j<=2;j++)
scanf("%dt",&a[i][j]);
}
printf("n%dt%dn%dt%d", a[1][1],a[1][2],a[2][1],a[2][2]);
}
c for-loop
c for-loop
edited Jan 2 at 9:24
Mat
166k29316347
asked Jan 2 at 9:21
F.FredF.Fred
62
edited Jan 2 at 9:24
Mat
166k29316347
asked Jan 2 at 9:21
F.FredF.Fred
62
edited Jan 2 at 9:24
Mat
166k29316347
edited Jan 2 at 9:24
Mat
166k29316347
edited Jan 2 at 9:24
Mat
166k29316347
166k29316347
asked Jan 2 at 9:21
F.FredF.Fred
62
asked Jan 2 at 9:21
F.FredF.Fred
62
asked Jan 2 at 9:21
F.FredF.Fred
62
62
When you declare an array with two entries, likea[2], the only valid indexes are 0 and 1. But the loops and the printf are using indexes 1 and 2. One solution is to make the array biggerint a[3][3].
– user3386109
Jan 2 at 9:26
1
In C the array starts at 0 not 1, so the declared arraya[2][2]containsa[0][0]uptoa[1][1].
– Tom Kuschel
Jan 2 at 9:28
a[1][2]anda[2][1]anda[2][2]do not exist. Your array has 4 elements:a[0][0],a[0][1],a[1][0], anda[1][1].
– pmg
Jan 2 at 9:28
thanks for the advice... but It doesn't seem to work that way.. it is what we define in the for loop as i am able to get the results as expected. When i printed, a[0][0]..a[1][1], all values except a[1][1] had zeroes..
– F.Fred
Jan 2 at 10:03
Read How to debug small programs.
– Basile Starynkevitch
Jan 2 at 10:12
add a comment |
When you declare an array with two entries, likea[2], the only valid indexes are 0 and 1. But the loops and the printf are using indexes 1 and 2. One solution is to make the array biggerint a[3][3].
– user3386109
Jan 2 at 9:26
1
In C the array starts at 0 not 1, so the declared arraya[2][2]containsa[0][0]uptoa[1][1].
– Tom Kuschel
Jan 2 at 9:28
a[1][2]anda[2][1]anda[2][2]do not exist. Your array has 4 elements:a[0][0],a[0][1],a[1][0], anda[1][1].
– pmg
Jan 2 at 9:28
thanks for the advice... but It doesn't seem to work that way.. it is what we define in the for loop as i am able to get the results as expected. When i printed, a[0][0]..a[1][1], all values except a[1][1] had zeroes..
– F.Fred
Jan 2 at 10:03
Read How to debug small programs.
– Basile Starynkevitch
Jan 2 at 10:12
When you declare an array with two entries, like
a[2], the only valid indexes are 0 and 1. But the loops and the printf are using indexes 1 and 2. One solution is to make the array bigger int a[3][3].– user3386109
Jan 2 at 9:26
When you declare an array with two entries, like
a[2], the only valid indexes are 0 and 1. But the loops and the printf are using indexes 1 and 2. One solution is to make the array bigger int a[3][3].– user3386109
Jan 2 at 9:26
1
1
In C the array starts at 0 not 1, so the declared array
a[2][2] contains a[0][0] upto a[1][1].– Tom Kuschel
Jan 2 at 9:28
In C the array starts at 0 not 1, so the declared array
a[2][2] contains a[0][0] upto a[1][1].– Tom Kuschel
Jan 2 at 9:28
a[1][2] and a[2][1] and a[2][2] do not exist. Your array has 4 elements: a[0][0], a[0][1], a[1][0], and a[1][1].– pmg
Jan 2 at 9:28
a[1][2] and a[2][1] and a[2][2] do not exist. Your array has 4 elements: a[0][0], a[0][1], a[1][0], and a[1][1].– pmg
Jan 2 at 9:28
thanks for the advice... but It doesn't seem to work that way.. it is what we define in the for loop as i am able to get the results as expected. When i printed, a[0][0]..a[1][1], all values except a[1][1] had zeroes..
– F.Fred
Jan 2 at 10:03
thanks for the advice... but It doesn't seem to work that way.. it is what we define in the for loop as i am able to get the results as expected. When i printed, a[0][0]..a[1][1], all values except a[1][1] had zeroes..
– F.Fred
Jan 2 at 10:03
Read How to debug small programs.
– Basile Starynkevitch
Jan 2 at 10:12
Read How to debug small programs.
– Basile Starynkevitch
Jan 2 at 10:12
add a comment |
2 Answers
2
active
oldest
votes
2
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=0;i<2;i++) /*go through rows - arrays in c go [0- (n-1)]*/
{
for(j=0;j<2;j++)/*go through col */
scanf("%d",&a[i][j]); /*remove t- now will scan 4 values only */
}
printf("n%dt%dn%dt%d", a[0][0],a[0][1],a[1][0],a[1][1]);
return 0;
}
answered Jan 2 at 9:44
H.cohenH.cohen
47018
Thanks a lot.. the tab was trouble some 't'. I have one more q. when i added one more matrix with the 't' say b[2][2] in the same program(int i,j,m,n,a[2][2],b[2][2], then the fifth value that got entered after a[1][1] appeared as the first value in the b[0][0]. Where was it stored then?(should i specify the code?)
– F.Fred
Jan 2 at 9:49
add a comment |
4
You have declared this
int a[2][2];
which has four items, a[0][0], a[0][1], a[1][0] and a[1][1].
However, you are starting your indexing at 1 and going up to 2, so are stepping out of bounds which is undefined behaviour.
Anything can then happen.
Change your loops i.e.:
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
// as you were
to index from 0.
You also need to consider your printf statement, since that oversteps too.
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
True... Added an edit to point out that needs thought too.
– doctorlove
Jan 2 at 9:36
Thanks for the help,. when i tried with my original program, i mean for(i=1;i<2;i++), i still get the results with a comment as such " *** stack smashing detected ***: ./a.out terminated Aborted (core dumped)".. Why is that so? should i understand something more?
– F.Fred
Jan 2 at 9:59
When you tried what with your original program? Have you sorted theprintfstatement? If you have a core dump, you can load it in the debugger to see what went wrong where. Concentrate on making sure you don't try to access[2]ina- for either index though.
– doctorlove
Jan 2 at 10:13
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
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2
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=0;i<2;i++) /*go through rows - arrays in c go [0- (n-1)]*/
{
for(j=0;j<2;j++)/*go through col */
scanf("%d",&a[i][j]); /*remove t- now will scan 4 values only */
}
printf("n%dt%dn%dt%d", a[0][0],a[0][1],a[1][0],a[1][1]);
return 0;
}
answered Jan 2 at 9:44
H.cohenH.cohen
47018
Thanks a lot.. the tab was trouble some 't'. I have one more q. when i added one more matrix with the 't' say b[2][2] in the same program(int i,j,m,n,a[2][2],b[2][2], then the fifth value that got entered after a[1][1] appeared as the first value in the b[0][0]. Where was it stored then?(should i specify the code?)
– F.Fred
Jan 2 at 9:49
add a comment |
2
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=0;i<2;i++) /*go through rows - arrays in c go [0- (n-1)]*/
{
for(j=0;j<2;j++)/*go through col */
scanf("%d",&a[i][j]); /*remove t- now will scan 4 values only */
}
printf("n%dt%dn%dt%d", a[0][0],a[0][1],a[1][0],a[1][1]);
return 0;
}
answered Jan 2 at 9:44
H.cohenH.cohen
47018
Thanks a lot.. the tab was trouble some 't'. I have one more q. when i added one more matrix with the 't' say b[2][2] in the same program(int i,j,m,n,a[2][2],b[2][2], then the fifth value that got entered after a[1][1] appeared as the first value in the b[0][0]. Where was it stored then?(should i specify the code?)
– F.Fred
Jan 2 at 9:49
add a comment |
2
2
2
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=0;i<2;i++) /*go through rows - arrays in c go [0- (n-1)]*/
{
for(j=0;j<2;j++)/*go through col */
scanf("%d",&a[i][j]); /*remove t- now will scan 4 values only */
}
printf("n%dt%dn%dt%d", a[0][0],a[0][1],a[1][0],a[1][1]);
return 0;
}
answered Jan 2 at 9:44
H.cohenH.cohen
47018
#include <stdio.h>
int main()
{
int i,j,a[2][2];
for(i=0;i<2;i++) /*go through rows - arrays in c go [0- (n-1)]*/
{
for(j=0;j<2;j++)/*go through col */
scanf("%d",&a[i][j]); /*remove t- now will scan 4 values only */
}
printf("n%dt%dn%dt%d", a[0][0],a[0][1],a[1][0],a[1][1]);
return 0;
}
answered Jan 2 at 9:44
H.cohenH.cohen
47018
answered Jan 2 at 9:44
H.cohenH.cohen
47018
answered Jan 2 at 9:44
H.cohenH.cohen
47018
answered Jan 2 at 9:44
H.cohenH.cohen
47018
47018
Thanks a lot.. the tab was trouble some 't'. I have one more q. when i added one more matrix with the 't' say b[2][2] in the same program(int i,j,m,n,a[2][2],b[2][2], then the fifth value that got entered after a[1][1] appeared as the first value in the b[0][0]. Where was it stored then?(should i specify the code?)
– F.Fred
Jan 2 at 9:49
add a comment |
Thanks a lot.. the tab was trouble some 't'. I have one more q. when i added one more matrix with the 't' say b[2][2] in the same program(int i,j,m,n,a[2][2],b[2][2], then the fifth value that got entered after a[1][1] appeared as the first value in the b[0][0]. Where was it stored then?(should i specify the code?)
– F.Fred
Jan 2 at 9:49
Thanks a lot.. the tab was trouble some 't'. I have one more q. when i added one more matrix with the 't' say b[2][2] in the same program(int i,j,m,n,a[2][2],b[2][2], then the fifth value that got entered after a[1][1] appeared as the first value in the b[0][0]. Where was it stored then?(should i specify the code?)
– F.Fred
Jan 2 at 9:49
Thanks a lot.. the tab was trouble some 't'. I have one more q. when i added one more matrix with the 't' say b[2][2] in the same program(int i,j,m,n,a[2][2],b[2][2], then the fifth value that got entered after a[1][1] appeared as the first value in the b[0][0]. Where was it stored then?(should i specify the code?)
– F.Fred
Jan 2 at 9:49
add a comment |
4
You have declared this
int a[2][2];
which has four items, a[0][0], a[0][1], a[1][0] and a[1][1].
However, you are starting your indexing at 1 and going up to 2, so are stepping out of bounds which is undefined behaviour.
Anything can then happen.
Change your loops i.e.:
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
// as you were
to index from 0.
You also need to consider your printf statement, since that oversteps too.
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
True... Added an edit to point out that needs thought too.
– doctorlove
Jan 2 at 9:36
Thanks for the help,. when i tried with my original program, i mean for(i=1;i<2;i++), i still get the results with a comment as such " *** stack smashing detected ***: ./a.out terminated Aborted (core dumped)".. Why is that so? should i understand something more?
– F.Fred
Jan 2 at 9:59
When you tried what with your original program? Have you sorted theprintfstatement? If you have a core dump, you can load it in the debugger to see what went wrong where. Concentrate on making sure you don't try to access[2]ina- for either index though.
– doctorlove
Jan 2 at 10:13
add a comment |
4
You have declared this
int a[2][2];
which has four items, a[0][0], a[0][1], a[1][0] and a[1][1].
However, you are starting your indexing at 1 and going up to 2, so are stepping out of bounds which is undefined behaviour.
Anything can then happen.
Change your loops i.e.:
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
// as you were
to index from 0.
You also need to consider your printf statement, since that oversteps too.
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
True... Added an edit to point out that needs thought too.
– doctorlove
Jan 2 at 9:36
Thanks for the help,. when i tried with my original program, i mean for(i=1;i<2;i++), i still get the results with a comment as such " *** stack smashing detected ***: ./a.out terminated Aborted (core dumped)".. Why is that so? should i understand something more?
– F.Fred
Jan 2 at 9:59
When you tried what with your original program? Have you sorted theprintfstatement? If you have a core dump, you can load it in the debugger to see what went wrong where. Concentrate on making sure you don't try to access[2]ina- for either index though.
– doctorlove
Jan 2 at 10:13
add a comment |
4
4
4
You have declared this
int a[2][2];
which has four items, a[0][0], a[0][1], a[1][0] and a[1][1].
However, you are starting your indexing at 1 and going up to 2, so are stepping out of bounds which is undefined behaviour.
Anything can then happen.
Change your loops i.e.:
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
// as you were
to index from 0.
You also need to consider your printf statement, since that oversteps too.
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
You have declared this
int a[2][2];
which has four items, a[0][0], a[0][1], a[1][0] and a[1][1].
However, you are starting your indexing at 1 and going up to 2, so are stepping out of bounds which is undefined behaviour.
Anything can then happen.
Change your loops i.e.:
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
// as you were
to index from 0.
You also need to consider your printf statement, since that oversteps too.
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
edited Jan 2 at 10:11
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
answered Jan 2 at 9:31
doctorlovedoctorlove
14.8k23051
14.8k23051
True... Added an edit to point out that needs thought too.
– doctorlove
Jan 2 at 9:36
Thanks for the help,. when i tried with my original program, i mean for(i=1;i<2;i++), i still get the results with a comment as such " *** stack smashing detected ***: ./a.out terminated Aborted (core dumped)".. Why is that so? should i understand something more?
– F.Fred
Jan 2 at 9:59
When you tried what with your original program? Have you sorted theprintfstatement? If you have a core dump, you can load it in the debugger to see what went wrong where. Concentrate on making sure you don't try to access[2]ina- for either index though.
– doctorlove
Jan 2 at 10:13
add a comment |
True... Added an edit to point out that needs thought too.
– doctorlove
Jan 2 at 9:36
Thanks for the help,. when i tried with my original program, i mean for(i=1;i<2;i++), i still get the results with a comment as such " *** stack smashing detected ***: ./a.out terminated Aborted (core dumped)".. Why is that so? should i understand something more?
– F.Fred
Jan 2 at 9:59
When you tried what with your original program? Have you sorted theprintfstatement? If you have a core dump, you can load it in the debugger to see what went wrong where. Concentrate on making sure you don't try to access[2]ina- for either index though.
– doctorlove
Jan 2 at 10:13
True... Added an edit to point out that needs thought too.
– doctorlove
Jan 2 at 9:36
True... Added an edit to point out that needs thought too.
– doctorlove
Jan 2 at 9:36
Thanks for the help,. when i tried with my original program, i mean for(i=1;i<2;i++), i still get the results with a comment as such " *** stack smashing detected ***: ./a.out terminated Aborted (core dumped)".. Why is that so? should i understand something more?
– F.Fred
Jan 2 at 9:59
Thanks for the help,. when i tried with my original program, i mean for(i=1;i<2;i++), i still get the results with a comment as such " *** stack smashing detected ***: ./a.out terminated Aborted (core dumped)".. Why is that so? should i understand something more?
– F.Fred
Jan 2 at 9:59
When you tried what with your original program? Have you sorted the
printf statement? If you have a core dump, you can load it in the debugger to see what went wrong where. Concentrate on making sure you don't try to access [2] in a - for either index though.– doctorlove
Jan 2 at 10:13
When you tried what with your original program? Have you sorted the
printf statement? If you have a core dump, you can load it in the debugger to see what went wrong where. Concentrate on making sure you don't try to access [2] in a - for either index though.– doctorlove
Jan 2 at 10:13
add a comment |
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When you declare an array with two entries, like
a[2], the only valid indexes are 0 and 1. But the loops and the printf are using indexes 1 and 2. One solution is to make the array biggerint a[3][3].– user3386109
Jan 2 at 9:26
1
In C the array starts at 0 not 1, so the declared array
a[2][2]containsa[0][0]uptoa[1][1].– Tom Kuschel
Jan 2 at 9:28
a[1][2]anda[2][1]anda[2][2]do not exist. Your array has 4 elements:a[0][0],a[0][1],a[1][0], anda[1][1].– pmg
Jan 2 at 9:28
thanks for the advice... but It doesn't seem to work that way.. it is what we define in the for loop as i am able to get the results as expected. When i printed, a[0][0]..a[1][1], all values except a[1][1] had zeroes..
– F.Fred
Jan 2 at 10:03
Read How to debug small programs.
– Basile Starynkevitch
Jan 2 at 10:12