Wednesday, June 13, 2012

List Warning codes in C programming

Warning code in C programming


Complete list of warning codes in c programming language


S.N.
Warning message
Code
ANSI Violations
1
Assigning 'type' to 'enumeration'
eas
2
Bit fields must be signed or unsigned int
bbf
3
Both return and return with a value used
ret
4
Declare type 'type' prior to use in prototype
dpu
5
Division by zero
zdi
6
Hexadecimal value contains more than 3 digits
big
7
Initializing 'enumeration' with 'type'
bei
8
'identifier' is declared as both external and static
ext
9
Ill-formed pragma
ill
10
Initialization is only partially bracketed
pin
11
Redefinition of 'macro' is not identical
dup
12
Suspicious pointer conversion
sus
13
Undefined structure 'structure'
stu
14
Void functions may not return a value
voi
Frequent Errors
1
Code has no effect
eff
2
Function should return a value
rvl
3
Parameter 'parameter' is never used
par
4
Possible use of 'identifier' before definition
def
5
Possibly incorrect assignment
pia
6
Unreachable code
rch
Less Frequent Errors
1
Ambiguous operators need parentheses
amb
2
Array variable 'identifier' is near
ias
3
Call to function with no prototype
pro
4
Call to function 'function' with no prototype
pro
5
Condition is always false
wccc
6
Condition is always true
wccc
7
'identifier' declared but never used
use
8
'identifier' is assigned a value that is never used
aus
9
No declaration for function 'function'
nod
10
Structure passed by value
stv
11
Superfluous & with function
amp
Portability Warnings
1
Constant is long
cln
2
Constant out of range in comparison
rng
3
Conversion may lose significant digits
sig
4
Non portable pointer comparison
cpt
5
Non portable pointer conversion
rpt
6
Mixing pointers to signed and unsigned char
ucp

Arrays in c

Arrays in c


Array tutorials in c programming language by examples


An array is derived data type in c programming language which can store similar type of data in continuous memory location. Data may be primitive type (int, char, float, double…), address of union, structure, pointer, function or another array.

Example of array declaration:

int arr[5];
char arr[5];
float arr[5];
long double arr[5];
char * arr[5];
int (arr[])();
double ** arr[5];
Array is useful when:

(a) We have to store large number of data of similar type. If we have large number of similar kind of variable then it is very difficult to remember name of all variables and write the program. For example:
//PROCESS ONE
#include
int main(){
    int ax=1;
    int b=2;
    int cg=5;
    int dff=7;
    int am=8;
    int raja=0;
    int rani=11;
    int xxx=5;
    int yyy=90;
    int p;
    int q;
    int r;
    int avg;
    avg=(ax+b+cg+dff+am+raja+rani+xxx+yyy+p+q+r)/12;
    printf("%d",avg);

    return 0;        
}
If we will use array then above program can be written as:
//PROCESS TWO
#include
int main(){
    int arr[]={1,2,5,7,8,0,11,5,50};
    int i,avg;
    for(int i=0;i<12;i++){
         avg=avg+arr[i];
    }
    printf("%d",avg/12);
    return 0;        
}
Question: Write a C program to find out average of 200 integer number using process one and two.
(b) We want to store large number of data in continuous memory location. Array always stores data in continuous memory location.
(q) What will be output when you will execute the following program?

#include
int main(){
int arr[]={0,10,20,30,40};
    char *ptr=arr;
    arr=arr+2;
    printf("%d",*arr);
    return 0;        
}
Advantage of using array:
1. An array provides singe name .So it easy to remember the name of all element of an array.

2. Array name gives base address of an array .So with the help increment operator we can visit one by one all the element of an array.

3. Array has many application data structure.
Array of pointers in c:

        Array whose content is address of another variable is known as array pointers.  For example:

#include
int main(){
float a=0.0f,b=1.0f,c=2.0f;
    float * arr[]={&a,&b,&c};
    b=a+c;
    printf("%f",arr[1]);
    return 0;        
}


Complex arrays in c

1. Declaration of an array of size five which can store address such functions whose parameter is void data type and return type is also void data type:
void ( arr[5] )( );
2. Declaration of an array of size five which can store address such function which has two parameter of int data type and return type is  float data type:
float ( arr[5] )(int, int);
3. Declaration of an array of size two which can store the address of printf or sacanf function:
int ( arr[2] )( const char *, … );
Note: prototype of printf function is:  int printf( const char *, … );
Different type of array in c:
(a) Array of integer
    An array which can hold integer data type is known as array of integer.

(b) Array of character
    An array which can hold character data type is known as array of character.
(c) Array of union
    An array which can hold address of union data type is known as union of integer.

For example:
(1) What will be output when you will execute the following program?

#include
union A{
char p;
float const * const q;
};
int main(){
    union A arr[10];
    printf("%d",sizeof arr);
   return 0;      
}
  
Output: 20
(2) What will be output when you will execute the following program?
#include
union A{
    char character;
    int ascii;
};
int main(){
    union A arr[2]={{65},{'a'}};
    printf("%c %c",arr[0],arr[1]);
       return 0;      
}
  
Output: A a
(d) Array of structure
 An array which can hold address of structure data type is known as array of structure. For example:
(1) What will be output when you will execute the following program?


#include
typedef struct stu{
    char * name;
    int roll;
}s;
int main(){
    s arr[2]={{"raja",10},{"rani",11}};
    printf("%s %d",arr[0]);
    return 0;        
}
Output: raja 10
(2) What will be output when you will execute the following program?


#include
struct A{
    int p;
    float q;
    long double *r;
};
int main(){
    struct A arr[10];
    printf("%d",sizeof arr);
   
    return 0;        
}
Output: 80
(e) Array of string
    An array which can hold integer data type is known as array of integer.
(f) Array of array
    An array which can hold address of another array is known as array of array.
(g) Array of address of integer
    An array which can hold address integer data type is known as array of address of integer.
Pointer to array

A pointer which holds base address of an array or address of any element of an array is known as pointer to array. For example:
(a)

#include
int main(){
    int arr[5]={100,200,300};
    int *ptr1=arr;
    char *ptr2=(char *)arr;
    printf("%d   %d",*(ptr1+2),*(ptr2+4));

       return 0;       
}
Output: 300   44

(b)

#include
int main(){
    static int a=11,b=22,c=33;
    int * arr[5]={&a,&b,&c};
    int const * const *ptr=&arr[1];
    --ptr;
    printf("%d ",**ptr);
        return 0;        
}
Output: 11