Mistake 1 .Constant Expression Require

#include<stdio.h>
void main()
{
int i=10;
int a[i];
}

• i is initialized to 10.
• Using a[i] does not mean a[10] because 'i' is Integer Variable whose value can be changed inside program.

Instead of it Write it as -

#include<stdio.h>
void main()
{
const int i=10;
int a[i];
}

because -

• Value of Const Variable cannot be changed once initialized.

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Mistake 2 .Empty Valued

#include<stdio.h>
void main()
{
int a[];
}

• a is Unknown Here or Empty.
• Size of Array should be Specified as a Constant Value.

Instead of it Write it as -

#include<stdio.h>
void main()
{
int a[] = {1,1};
}

• After writing it default size of Array is 2.

#include<stdio.h>
void main()
{
int a[] = {}; // This also Cause an Error
}

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Mistake 3 .Does Not Checks Bound Checking

#include<stdio.h>
void main()
{
int a[5];
printf("%d",a[7]);
}

• Here Array size specified is 5.
• So we have Access to Following Array Elements - a[0],a[1],a[2],a[3],a[4]
• But accessing a[5] causes Garbage  Value to be used because C Does not performs Array Bound Check.
• So One Should access values upto [Maximum - 1]

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Mistake 4 .Case Sensitive

#include<stdio.h>
void main()
{
int a[5];
printf("%d",A[2]);
}

• Array Variable is Case Sensitive so A[2] does not print anything it Displays Error Message : "Undefined Symbol A"

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Some Tips :

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Tip 1 : Use #define to Specify Array Size

#include<stdio.h>
#define MAX 5
void main()
{
int a[MAX];
printf("%d",a[2]);
}

• As MAX is replaced by 5 for every Occurrence , So In due Course of time if you want to increase or decrease Size of array then change should be made in

#define MAX 10

Tip 2 : a[i] and i[a] are Same 
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Tags / Keywords : | 1-D Array, Common Mistakes, Error : Mistakes

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