5 String

//How to convert string to int without using library functions in c

#include<stdio.h>

int stringToInt(char[] );
int main(){

    char str[10];
    int intValue;

    printf("Enter any integer as a string: ");
    scanf("%s",str);

   intValue = stringToInt(str);

    printf("Equivalent integer value: %d",intValue);

    return 0;
}

int stringToInt(char str[]){
    int i=0,sum=0;

    while(str[i]!='\0'){
         if(str[i]< 48 || str[i] > 57){
             printf("Unable to convert it into integer.\n");
             return 0;
         }
         else{
             sum = sum*10 + (str[i] - 48);
             i++;
         }

    }

    return sum;

}

Sample output:
Enter any integer as a string: 123
Equivalent integer value: 123

//COUNTING DIFFERENT CHARACTERS IN A STRING USING C PROGRAM

#include <stdio.h>
int isvowel(char chk);
int main(){
  char text[1000], chk;
  int count;
  count = 0;
  while((text[count] = getchar()) != '\n')
            count++;
  text[count] = '\0';
  count = 0;
  while ((chk = text[count]) != '\0'){
      if (isvowel(chk)){
           if((chk = text[++count]) && isvowel(chk)){
               putchar(text[count -1]);
              putchar(text[count]);
              putchar('\n');
           }
      }
      else
           ++count;
  }
  return 0;
}
int isvowel(char chk){
  if(chk == 'a' || chk == 'e' || chk == 'i' || chk == 'o' || chk == 'u')
      return 1;
  return 0;
}

//SORTING OF STRING USING C PROGRAM

#include<stdio.h>
int main(){
  int i,j,n;
  char str[20][20],temp[20];
  puts("Enter the no. of string to be sorted");
  scanf("%d",&n);
  for(i=0;i<=n;i++)
      gets(str[i]);
  for(i=0;i<=n;i++)
      for(j=i+1;j<=n;j++){
           if(strcmp(str[i],str[j])>0){
               strcpy(temp,str[i]);
              strcpy(str[i],str[j]);
              strcpy(str[j],temp);
           }
      }
  printf("The sorted string\n");
  for(i=0;i<=n;i++)
      puts(str[i]);
  return 0;
}

//CONCATENATION OF TWO STRINGS USING C PROGRAM

#include<stdio.h>
int main(){
  int i=0,j=0;
  char str1[20],str2[20];
  puts("Enter first string");
  gets(str1);
  puts("Enter second string");
  gets(str2);
  printf("Before concatenation the strings are\n");
  puts(str1);
  puts(str2);
  while(str1[i]!='\0'){
      i++;
  }
  while(str2[j]!='\0'){
      str1[i++]=str2[j++];
  }
  str1[i]='\0';
  printf("After concatenation the strings are\n");
  puts(str1);
return 0;
}

//CONCATENATION OF TWO STRINGS USING POINTER IN C PROGRAM

#include<stdio.h>
int main(){
  int i=0,j=0;
  char *str1,*str2,*str3;
  puts("Enter first string");
  gets(str1);
  puts("Enter second string");
  gets(str2);
  printf("Before concatenation the strings are\n");
  puts(str1);
  puts(str2);
  while(*str1){
      str3[i++]=*str1++;
  }
  while(*str2){
      str3[i++]=*str2++;
  }
  str3[i]='\0';
  printf("After concatenation the strings are\n");
  puts(str3);
  return 0;
}

//Write a c program which prints initial of any name

#include<stdio.h>
int main(){
   char str[20];
   int i=0;
   printf("Enter a string: ");
   gets(str);
   printf("%c",*str);
   while(str[i]!='\0'){
       if(str[i]==' '){
            i++;
            printf("%c",*(str+i));
       }
       i++;
   }
   return 0;
}

Sample output:

Enter a string: Robert De Niro
RDN

//Write a c program to print the string from given character

#include<string.h>
#include<stdio.h>
int main(){
  char *p;
  char s[20],s1[1];
  printf("\nEnter a string: ");
  scanf("%[^\n]",s);
  fflush(stdin);
  printf("\nEnter character: ");
  gets(s1);
  p=strpbrk(s,s1);
  printf("\nThe string from the given character is: %s",p);
  return 0;
}

//Write a c program to reverse a string

Reverse a string in c without using temp
String reverse using strrev in c programming language

#include<stdio.h>
#include<string.h>
int main(){
    char str[50];
    char *rev;
    printf("Enter any string : ");
    scanf("%s",str);
    rev = strrev(str);

    printf("Reverse string is : %s",rev);

    return 0;
}

String reverse in c without using strrev
String reverse in c without using string function
How to reverse a string in c without using reverse function

#include<stdio.h>
int main(){
    char str[50];
    char rev[50];
    int i=-1,j=0;

    printf("Enter any string : ");
    scanf("%s",str);

    while(str[++i]!='\0');

    while(i>=0)
     rev[j++] = str[--i];

    rev[j]='\0';

    printf("Reverse of string is : %s",rev);

    return 0;
}

/String concatenation in c without using strcat

#include<stdio.h>

void stringConcat(char[],char[]);
int main(){

    char str1[100],str2[100];
    int compare;

    printf("Enter first string: ");
    scanf("%s",str1);

    printf("Enter second string: ");
    scanf("%s",str2);

    stringConcat(str1,str2);

    printf("String after concatenation: %s",str1);

    return 0;
}

void stringConcat(char str1[],char str2[]){
    int i=0,j=0;


    while(str1[i]!='\0'){
         i++;
    }

    while(str2[j]!='\0'){
         str1[i] = str2[j];
         i++;
         j++;
    }

    str1[i] = '\0';
}

ample output:
Enter first string: ameer
Enter second string: @hamza
String after concatenation: amee@rhamza

//How to compare two strings in c without using strcmp

#include<stdio.h>

int stringCompare(char[],char[]);
int main(){

    char str1[100],str2[100];
    int compare;

    printf("Enter first string: ");
    scanf("%s",str1);

    printf("Enter second string: ");
    scanf("%s",str2);

    compare = stringCompare(str1,str2);

    if(compare == 1)
         printf("Both strings are equal.");
    else
         printf("Both strings are not equal");

    return 0;
}

int stringCompare(char str1[],char str2[]){
    int i=0,flag=0;

    while(str1[i]!='\0' && str2[i]!='\0'){
         if(str1[i]!=str2[i]){
             flag=1;
             break;
         }
         i++;
    }

    if (flag==0 && str1[i]=='\0' && str2[i]=='\0')
         return 1;
    else
         return 0;

}

//program for convert a given sentence into the first letter of each word should be upper case remaining are lower case

#include<stdio.h>
#include<string.h>

int main(){

char str[100];
int i,flag = 1;

printf("Enter any string: ");
scanf("%[^\n]",str);

for(i=0;i<=strlen(str);i++){

if(str[i] == 32){
flag=1;
}
else if(flag ==1){

if(str[i]>=97&&str[i]<=122)
str[i]=str[i]-32; flag =0; }
else{
if(str[i]>=65&&str[i]<=90)
str[i]=str[i]+32;
}
}

printf("\nNew String is: %s",str);
return 0;

}

Sample output:

Enter any string: learning proramming in c

New String is: Learning Proramming In C

//Reverse a string using recursion in c

#include<stdio.h>
#define MAX 100
char* getReverse(char[]);

int main(){

    char str[MAX],*rev;

    printf("Enter  any string: ");
    scanf("%s",str);

    rev = getReverse(str);

    printf("Reversed string is: %s",rev);
    return 0;
}

char* getReverse(char str[]){

    static int i=0;
    static char rev[MAX];

    if(*str){
         getReverse(str+1);
         rev[i++] = *str;
    }

    return rev;
}

Sample output:

Enter any string: mona
Reversed string is: anom

//Write a c program to reverse a string

Reverse a string in c without using temp
String reverse using strrev in c programming language

#include<stdio.h>
#include<string.h>
int main(){
    char str[50];
    char *rev;
    printf("Enter any string : ");
    scanf("%s",str);
    rev = strrev(str);
 
    printf("Reverse string is : %s",rev);
 
    return 0;
}

String reverse in c without using strrev
String reverse in c without using string function
How to reverse a string in c without using reverse function

#include<stdio.h>
int main(){
    char str[50];
    char rev[50];
    int i=-1,j=0;

    printf("Enter any string : ");
    scanf("%s",str);
 
    while(str[++i]!='\0');

    while(i>=0)
     rev[j++] = str[--i];

    rev[j]='\0';

    printf("Reverse of string is : %s",rev);

    return 0;
}

Sample output:
Enter any string : ameerhamza
Reverse of string is : azmahreema