UNIT - 3 ARRAYS AND STRINGS

Array An Array is a collection of similar data items, that are stored under a common name. Types –One-Dimensional array –Two-Dimensional array – Multi-Dimensional array

One-Dimensional array Array Declaration Syntax: data_type array_name[size]; Example: int x[3]; X[0] X[1] X[2] x

Array initialization At compile time At run time

At compile time Syntax: data_type array_name[size]={variables}; Example: int x[3]={5,3,7}; X[0] X[1] X[2] x

At Run time Array can also initialize at the run time. Example: while(i<10) { if(i<5) sum[i]=0; else sum[i]=sum[i]+i; }

Example: scanf(“%d%d”,&a[0],&a[1]);

Example #include void main() { int x[2],i; printf("\nEnter the inputs:"); for(i=0;i<2;i++) scanf("%d",&x[i]); for(i=0;i<2;i++) printf("\nThe value in x[%d] is %d",i,x[i]); getch(); }

Output Enter the inputs:3 6 The value in x[0] is 3 The value in x[1] is 6

Example #include void main() { int i; char x[5]={'a','b','c','d','e'}; clrscr(); for(i=0;i<5;i++) printf("\nThe value in x[%d] is %c",i,x[i]); getch(); }

Output The value in x[0] is a The value in x[1] is b The value in x[2] is c The value in x[3] is d The value in x[4] is e

Two-Dimensional array Array Declaration Syntax: data_type array_name[row_size] [col_size]; Example: int x[3][2]; X[0][0] X[1][0] X[2][0] Col 0 Col 1 row 0 row 1 row 2 X[0][1] X[1][1] X[2][1]

Array Initialization Syntax: data_type array_name[row_size] [col_size];={variables}; Example: int x[2][2]={1,50,2,75};

int x[2][2]={ {1,50}, {2,75} }; (or) int x[ ][2]={ {1,50}, {2,75} };

row 0 row 1 Col 0 Col 1

Example #include void main() { int i,j; int x[2][2]={{1,50}, {2,75} }; clrscr(); for(i=0;i<2;i++) for(j=0;j<2;j++) printf("\nThe value in x[%d][%d] is %d",i,j,x[i][j]); getch(); }

Output The value in x[0][0] is 1 The value in x[0][1] is 50 The value in x[1][0] is 2 The value in x[1][1] is 75

Example #include void main() { int i,j; int x[][2]={ {1,50},{2,75},{3,65}}; clrscr(); for(i=0;i<=2;i++) for(j=0;j<2;j++) printf("\nThe value in x[%d][%d] is %d",i,j,x[i][j]); getch(); }

Output The value in x[0][0] is 1 The value in x[0][1] is 50 The value in x[1][0] is 2 The value in x[1][1] is 75 The value in x[2][0] is 3 The value in x[2][1] is 65

Matrix Addition #include void main() { int i,j,k,r1,r2,c1,c2; int a[5][5],b[5][5],c[5][5]; clrscr(); step1: printf("\n Enter the size of matrix A:"); scanf("%d%d",&r1,&c1); printf("\n Enter the size of matrix B: "); scanf("%d%d",&r2,&c2); if((c1==c2)&&(r1==r2)) goto step2; else goto step1;

step2: printf("\n Enter the elements of matrix A \n"); for(i=0;i<r1;i++) { for(j=0;j<c1;j++) { scanf("%d",&a[i][j]); } printf("\n Enter the elements of matrix B \n"); for(i=0;i<r2;i++) { for(j=0;j<c2;j++) { scanf("\t%d",&b[i][j]); }

for(i=0;i<r1;i++) { for(j=0;j<c1;j++) { c[i][j]=0; c[i][j]=c[i][j]+a[i][j]+b[i][j]; } printf("\n The resultant matrix after addition of A & B is\n"); for(i=0;i<r1;i++) { for(j=0;j<c1;j++) printf("%d\t",c[i][j]); printf("\n"); } getch(); }

Output Enter the size of matrix A: 2 2 Enter the size of matrix B: 2 2 Enter the elements of matrix A 2 Enter the elements of matrix B 3 The resultant matrix after addition of A&B is 5

Matrix Multiplication #include void main() { int i,j,k,r1,r2,c1,c2; int a[5][5],b[5][5],c[5][5]; clrscr(); step1: printf("\n Enter the size of matrix A \n"); scanf("%d%d",&r1,&c1); printf("\n Enter the size of matrix B \n"); scanf("%d%d",&r2,&c2); if(c1==r2) goto step2; else goto step1;

step2: printf("\n Enter the elements of matrix A \n"); for(i=0;i<r1;i++) { for(j=0;j<c1;j++) { scanf("%d",&a[i][j]); } printf("\n Enter the elements of matrix B \n"); for(i=0;i<r2;i++) { for(j=0;j<c2;j++) { scanf("\t%d",&b[i][j]); }

for(i=0;i<r1;i++) { for(j=0;j<c2;j++) { c[i][j]=0; for(k=0;k<c1;k++) { c[i][j]=c[i][j]+a[i][k]*b[k][j]; } for(i=0;i<r1;i++) { for(j=0;j<c2;j++) printf("%d\t",c[i][j]); printf("\n"); } getch(); }

Output Enter the size of matrix A:2 2 Enter the size of matrix B:2 2 Enter the elements of matrix A 4 Enter the elements of matrix B 4 The resultant matrix is 32

Enter the size of matrix A:2 3 Enter the size of matrix B:3 2 Enter the elements of matrix A Enter the elements of matrix B

Passing array to Function Here an array is transferred as parameter to a function. void main() void fun(n,b[]) { void fun(int,int);int x,b[5]; int a[5],n;………….. ……………………….. fun(n,a); …………… } }

Example #include void add(int,int b[]); void main() { int a[5],i,n; clrscr(); printf("\n Enter the Number: "); scanf("%d",&n); printf("\n Enter the Values: "); for(i=0;i<n;i++) scanf("%d",&a[i]); add(n,a); }

void add(int x,int b[]) { int sum=0,i; for(i=0;i<x;i++) sum=sum+b[i]; printf("\nThe sum is: %d",sum); }

Output Enter the Number: 5 Enter the Values: The sum is: 15

Array of Characters In array the characters are terminated by the null (‘\0’) character. Example: char a[]={a,b,c}; abc\0

Example #include void main() { int i=0; char a[]="abcd"; clrscr(); while(a[i]!='\0') { printf("\t%c",a[i]); i++; }

Output a b c d

Multi Dimensional Array Syntax datatype array_name [size1][size2]….[size n] datatype- type of the data. array_name-name of the array. size-size of the array.

Example: int a[3][3][3]; Col 0 Col 1 Col 2 row 0 row 1 row 2 X[0][0] X[1][0] X[2][0] X[0][1] X[1][1] X[2][1] X[0][2] X[1][2] X[2][2]

String Functions strlen() It is used to find the length of the string. syntax: strlen(string) strcpy() It is used to copy one string to another. syntax: strcpy(string1,string2) strcat() It is used to combine two strings. syntax: strcat(string1,string2)

strcmp() It is used to compare two strings. syntax: strcmp(string1,string2) –Returns 0 if two strings are equal. –Return value <0 if s1 is less than s2. –Return value >0 if s1 is greater than s2. strrev() It used to reverse a string. syntax: strrev(string) strlwr(), strupr() It used to change the case of a string. syntax: strlwr(string) strupr(string)

strncpy() It used to copy ‘n’ characters of one string to another. strstr() –It is used to determine the first occurrence of a given string in another string. strncat() –It Appends source string to destination string upto specified length. strspn() –It is used t find upto what length two strings are identical.

strncmp() – It is used to compare ‘n’ character of two strings. strcmpi() – It is used to compare two strings without regarding the case. strnicmp() – It is used to compare first ‘n’ characters of two strings without regarding the case. strchr() – It is used to determine the first occurrence of a given character in a string. strrchr() – It is used to determine the last occurrence of a given character in a string.

Example #include void main() { char a[]="college"; int b; clrscr(); b=strlen(a); printf("\nThe length of the string is %d",b); getch(); } Output: The length of the string is 7

Example #include void main() { char a[]="IT"; char b[]="Dept"; clrscr(); strcpy(a,b); printf("\nThe string is %s",a); getch(); } Output: The string is Dept

Example #include void main() { char a[]="IT"; char b[]="Dept"; clrscr(); strcat(a,b); printf("\nThe string is %s",a); getch(); } Output: The string is ITDept

Example #include void main() { char a[]="itdept"; char b[]="it"; int i; clrscr(); i=strcmp(a,b); if(i==0) printf("\nstrings are equal:%d",i); else if(i<0) printf("\nstring1 is less than string2:%d",i);

else printf("\nstring1 is greater than string2:%d",i); getch(); } Output: string1 is greater than string2:100

Example #include void main() { char a[]="itdept"; clrscr(); printf("\nThe string is :%s",a); strupr(a); printf("\nThe string after conversion to uppercase :%s",a); strlwr(a); printf("\nThe string after conversion to lowercase :%s",a); getch(); }

Output The string is :itdept The string after conversion to uppercase :ITDEPT The string after conversion to lowercase :itdept

Example #include void main() { char a[]="Dept"; clrscr(); printf("\nThe string is %s",strrev(a)); getch(); } Output: The string is tpeD

Example #include void main() { char a[]="itdept"; char b[15]; int i=0; clrscr(); strncpy(b,a,2); b[2]='\0'; printf("\nThe string is :%s",b); getch(); }

Output: The string is :it

String Palindrome #include void main() { int len,i,j; char str[15]; clrscr(); printf("\n Enter the string:"); scanf("%s",str); len=strlen(str);

for(i=0,j=len-1;i<len/2;i++,j--) { if(str[i]!=str[j]) { printf("\nThe String is not a palindrome"); getch(); exit(0); } printf("\nThe String is a palindrome"); getch(); } Output: Enter the string:abcba The String is a palindrome

Enumerated Data Type It is user defined data type. The user can create their own data type and define some values to the variables. Syntax: enum tag_name { enum1; enum2; ………. };